Would seem that way. One girl (or guy) twenty times is preferred if (s)he’s someone I find genuinely attractive and care about but ten partners once if she isn’t and/or they have a strong resemblance to Salma Hayek, Natalie Portman, or Matt Damon.
Hell, I’d give up the dozens of sessions I had with my ex just for one more night with the girl before her.
Is the 20xer hot? Then yes. If not, then still yes.
I think the answer is age based really. I might have preferred, (to make it even) ten different experiences earlier, but at this point I’ve been around the block enough to say it’s about time to settle down. Since the dope is primarily older, you’re going to get almost exclusively the latter option: Been there, done a bunch, ready to settle down, and really BE with people. If you said 10 once vs. one ten times to a bunch of 16-20 year olds, you’d get a LOT more of the former promiscuous option, especially from the younger crowd. the context of the question is important.
Why limit yourself?
I was thinking about this, and upon further reflection I have to say this:
If it was 20 repeats of the worst sex I ever had, vs. 10 of the most mind blowing sex events I ever had (10 different girls does not preclude mind blowing sex) I would take the ten.
If on the other hand they were equal, hey I can count.
Count me as another person who never did 10 women at once. The logistics overwhelm me. I think that’s too many to do simultaneously. Two would be better, maybe three, but anymore and you’ve got to have people take numbers and wait. I guess if they’re all into each other, but not too much to the point where they care if you break into things, it could be OK.
Still, you would have to have an ego the size of Alaska to not worry that you weren’t just being set up and someone is going to blackmail you.
Can I get said woman cloned twenty times, and have them two at a time over five nights, two sessions a piece?
Male, heterosexual, monogamous(married)
I think I’d go for one, twenty times - because a significant part of the pleasure is being able to provoke maximum squirmy pleasure to the partner - and I reckon that takes a bit of practice and familiarity, as not everybody responds in the same way, or likes the same things done.
I agree with the age thing; when I was young and especially when I was drinking, the more the merrier. Now that I’m old and sober, one woman is by far the best.
True, but the OP didn’t say anything about love! 
I’m with Ruby, though…practice makes it better. Although that may be more true for us women than it is for men.
I’m going to have to go with one partner, 20x. I can also count. 
Male, non-religious, non-monogamous. I’ll take the 1 x 20, as I’ve found that quality generally increases as bodies and minds get to know each other.
Well, alright, I’ll break the chain. Ideally, I’d like Shibboleth’s plan - 4 people 5 times or 5 4 times or something like that. And I wouldn’t like 10 people AT ONCE - too many elbows and knees. But 10 people sequentially (well, 10 people, 1 at a time over a two month span, let’s say, otherwise we’ve overwhelmed my poor libido) vs. 1 person (that I don’t love any more or less than the 10 - only way to make it a fair comparison) 20 times? Oh, yeah. I’ll take the sampler plate!
Female, 32, polyamorous. And fond of qualifiers.
Why are the two choices mutually exclusive?
As awkward as new experiences sometimes are I’d go with the 10 women. Depends upon relative attractiveness/chemistry etc though.
Are we talking about setting me up with a total stranger for twenty sessions, or my soul mate?
Because if it’s the former, I may have to go with the ten. It seems better odds that I’d get someone I really clicked with, even if only once.
If we’re talking about this sex option as a subset of an otherwise fulfilling sex life (genie offers you 10 weeks of Saturday one night stands or 10 weeks of Friday/Saturday dates+sex with one girl) I’d go with 1x20 rather than 10x1. When you have an ongoing relationship, you can grow and explore your sexuality.
OTOH, if this is the entirety of your sex life (pre-lifelong-monogamy, or pre-celibacy) I’d go with the 10x1, the breadth of experience would be more interesting to look back on than a single relationship.
Male, straight. It would depend on the partner. I remember one woman who I just would not want to do it with again.
But with the right partner: 20 times with one woman.
Glad I’m not the only one who misread the title at first.
Blackmailed for what? Being awesome?
I suppose it depends (like am I banging Carmen Elektra 20 times vs ten pigs?) but I guess I would rather have variety. Then again, I live with my girlfriend and have access to plenty of single women in Manhattan so I guess I made my choice.
It’s not really that much of a hypothetical. Are people content with being single and playing the field or are they happy in committed relationships?
Still…variety can be nice.