The other big difference is that in parliamentary democracies, the Prime Minister is the leader of the majority party in Parliament, while in the U.S. the President is elected separately from Congress. So in the former, the majority party reliably has the ability to pass and implement its program, which is not the case in the U.S.
As a result, I would expect that the platforms and goals of each party are much clearer to the electorate on a continuing basis in a parliamentary democracy than in the U.S.
ETA: Take universal health care, for example: that has a history of coming and going as a Dem issue. Clinton ran on it in 1992, then after the midterm debacle of 1994, the Dems gave up on it until John Edwards forced it back into center stage in the 2008 cycle. But it took someone espousing it in the primary process to put it there.
So in the American system, ISTM that more time is needed to simply define what the issues are that are at stake.
If true, that may not be just an American thing. There was an interesting piece recently by a German journalist following the UK election in which, among other things, he touched on how vigorous the media scrutiny is. Apparently in Germany it is accepted that if you interview a politician, their press officers get sign-off on the interview before it is published. If you don’t like this convention, then, well, good luck getting any more interviews.
*"In Britain, journalists actually ask awkward questions. Watching [Evan] Davis demolish [Ed] Miliband may be painful for a Labour supporter, but for a journalist, no matter what your stance, it’s exhilarating.
If Davis tried that in Germany, though, he’d be out of a job."*
Formally speaking, the election campaign only starts a few weeks before polling (there are more generous rules about expenditure outside the election period).
But since Parliament has now limited the power of the Prime Minister to call for an election anywhere within the five-year period, we’ve known the date all along, and all the candidates for leading government office have been on display and about their business in Parliament. So in a sense campaigning (at least for good headlines) is non-stop, and particularly in the last year to eighteen months of a Parliament. In that sense, it’s not that different from your experience.
But what we don’t have is the possibility of anyone coming in for the top job without having served their apprenticeship in Parliament, and having been in their party leadership team for quite a while. Folk wisdom suggests that a party that doesn’t have its leadership team and campaign “narrative” in place for at least a couple of years before an election is likely to be at a disadvantage.