Or are they on a par? Or less of a deal? Or something else? 
Depends.
For non-Christians Thanksgiving can easily exceed Christmas in importance, especially as it is often a 4-day weekend allowing for visits to family.
For many Christians Christmas is more of a big deal.
Thanksgiving is often the much larger family gathering, although each family’s MMV. We used to get quite a group of relatives together for Thanksgiving, then celebrate Christmas just with the nuclear family.
Thanksgiving is one big meal with family followed by about a week of leftovers, and the only run-up to the holiday is that supermarkets usually have some sort of spending-rewards program to save up for a turkey for a couple of months in advance (and then sales on things like stuffing and pies for the week immediately prior).
Christmas, we start seeing sales for Christmas gifts some time in October or so, and starting some time in late November (hopefully but not always after Thanksgiving), everyone and everywhere has Christmas decorations up all over the place, and nonstop Christmas songs on every PA system. And then they go and have “special events” like “Christmas in July”, since it’s not enough already.
So Christmas is definitely a bigger deal.
Thanksgiving is an extended family holiday.
Christmas is a get together and get free crap that you’ll never use again holiday.
I prefer Thanksgiving.
The entire retail economy is based on Christmas. Thanksgiving is like a pre-holiday.
To some people, yes. I’ve always thought it’s a rather boring holiday, and it’s way too many days to spend with the family. 2-3 days is my limit!
Some people may prefer Thanksgiving, but by and large, Christmas is WAY bigger. People spend more, decorate more, send more cards, make more cookies, and go to more parties. I can think of hundreds of Christmas songs, and MAYBE one Thanksgiving song. No one puts up a Thanksgiving tree. Few people spend an entire month preparing for Thanksgiving. Santa Claus has a far better press agent than Tom Turkey. I’ve never heard of anyone going to a special midnight Thanksgiving service at church. (Though I’m sure it happens.)
No comparison.
Thanksgiving just lets everyone make Xmas plans and remind them what they want, gift-wise as well as for dinner.
I’m not sure how much sense this will make but … I think Thanksgiving can seem like the bigger deal because it’s more homogeneous. It’s a secular holiday so just about everyone celebrates it, and the way people celebrate is about the same – you eat a big meal. As a result, we have more of a uniform national Thanksgiving concept.
On the other hand, while Christmas is still a huge deal to people who are actually Christians, and many others who are not religious but enjoy it as a festive secular event, there are tons of differences in how people celebrate – for some, Christmas Eve is the big do, for others, it is Christmas morning, some are hard core religious and it’s Jesus-only, others are all about Santa. Then, obviously, the people who don’t celebrate at all.
So I don’t think Thanksgiving is a BIGGER deal than Christmas, but it’s an easier deal to market.
Thanksgiving doesn’t have anything like the economic impact Christmas has, so from that point of view, Christmas is a much bigger deal.
In my family, Thanksgiving is no big deal. I don’t go home to visit the parents or anything. Christmas is a command performance, at which I must appear or my mother will send out search parties to drag me in. Years ago, I dated a girl whose family was the exact opposite…Thanksgiving was their huge deal-must attend holiday, and Christmas was no biggie. Worked out well that way, but unfortunately she and I were not meant to be, so now she’s married to some dude and I’ll be watching football alone tommorrow.
I do go to church every Thanksgiving, but not at midnight. If it doesn’t fall on Sunday my church doesn’t have a service on Christmas. (Easter is the bigger deal for us)
My answer to the OP depends on the definition of “bigger” - No, I know what bigger means,the difference would be I guess, in what sense bigger is meant.
I’d like to think Thanksgiving is a bigger deal because it isn’t a religious hoilday. It doesn’t exclude people of other faiths than Christianity, or atheists or anyone. But I think the reality is more like what tdn posted. More $ per year per capita means Christmas is a bigger deal.
Christmas is, in general, a much bigger deal.
But, Thanksgiving is on a Thursay, and almost everyone except for service industry has both Thursday and Friday off. That makes it the one guarenteed 4 day weekend that most people get. So it is the easiest holiday to plan travel for.
Thanksgiving is the only real feast holiday we have left. It’s nowhere near as big a deal as Christmas in terms of cultural presence, though.
Both holidays have been ruined for me forever by my vile and evil half-brother and family, so it hardly matters. Bring me the damned bottle of wine, will you?
Thanksgiving is only really a big deal because it’s the opening act of the month-long holiday endurance event that is Christmas/Kwanzaa/Hannukah, ending on New Year’s. On it’s own, Thanksgiving would be no more important than Memorial Day or Labor Day: random holidays ostensibly devoted to family but which don’t really generate much interest or obligation for modern celebrants.
If Thanksgiving was in September, I doubt many people would care.
The four-day weekend is an interesting point. Everyone, everywhere, in every field gets Thursday and Friday off for Thanksgiving. Maybe you’ll occasionally see someone getting Wednesday off too as a “travel day”, but never more than that. For Christmas, on the other hand, it can vary from “Christmas itself off, and maybe a half-day on Christmas Eve”, to “the whole week from Christmas to New Year’s”, to “Three or four weeks off spanning Christmas, New Year’s, and some more at each end” (the last being mostly for schools).
This blanket statement is wrong, wrong, wrong! I do contract work for an environmental consulting firm, and they do not give their employees Friday off. Many of the companies that we consult for (usually telecom) do not give Friday off either. The same is true for many other jobs I’ve had. They’re all professional office jobs, but the employers force employees to take a vacation day to get Friday.
Also, consider service professions. Stores are open on Friday; some people have to work. My sister is a doctor; if you want Thanksgiving off, let alone Friday, you have to work during Christmas.
Every field except retail.
Thanksgiving is just a day off for people can deer hunt and exchange names for Christmas. It means squat for the circle of people I know, other than we have a day off to eat and hunt if we don’t work retail.
Christmas is the big deal.
The fact that Thanksgiving decorations take up one isle in a store when Christmas decorations take massive amounts of shelf space is a good indicator. Halloween takes up a lot more space than Thanksgiving. Valentines day takes up more space than Thanksgiving.
The difference is that Thanksgiving is basically a one-day event, while Christmas is an entire season. If you drive around on Thanksgiving, you’d likely not see anything related to the holiday. But driving around on Christmas, you’re reminded of the fact everywhere. And watching TV. And listening to the radio. And reading a paper or magazine. Christmas is everywhere.