On the wham bam thank you ma'am...

I don't think 90min or 2hrs would be in that category.
In my opinion you can have an hour appt and not be a wham bam thank you ma'am.
Granted there is not a lot of time but depending on the person you are with it can be just the right amount of time.
I enjoy multi-hr appts especially dinner/show dates and I have had the pleasure to go on quite a bit of these type of dates.I can't tell you how much fun these dates are I get to try new restaurants and foods I would probably never get a chance to try.
It is a way to get to know one another a little better before dessert.

I can't really break it down into percentages but if I had to give a wild estimate it would be 60% multi-hr and that is 3+ hrs and more that is what I am considering multi-hr and 40% of 60min-2hr appts with more of that leaning towards 90-2hr moreso than an hour.
I am probably off a little with my percentages.But you get a general idea.

My experience

I would say 30% are 1 hour dates, and 70% are 2 hours or more.  I like 1 hour dates as much as extended dates for different reasons

At home I'm squeezing in a session in between my life responsibilities.  

In Vegas I'm on vacation and alone. There are other things I like to do with girls other than the obvious. My favorite is to go dancing.  I can't dance alone and when I've tried to go out and "meet someone" it's been a disaster. It's too hard, I'm too old for that, plus I'm in this position where I have to lie about my marital status. My wife understands and is OK with my little vacations, but would be really upset if she found out I was dating a civvie. So I'm in a position where I have to either lie to my date or lie to my wife. Then there's the whole what do you do when you get back to the room, if that ever happens. Will she mind wearing sexy lingerie, will she do this, should I do that, what happens the next day.... I just don't see where it is worth it.  

I also like going to shows, and going alone sucks.  

My favorite date is to have a girl over for dinner, I usually have a time share with a full kitchen so I cook. It's fun. I try to make it a romantic fantasy.  

Biggest struggle is finding an "affordable" long date, and once finding one, making sure you can get along for the hours you booked. I've been very fortunate so far.

Was curious what the ratio was since I'm sure Vegas is different and I'm sure there's a higher number of multi-hour dinner/dancing/"dessert" dates.  I'm sure if a girl has a really low # of 60/90 minute dates, she might think those are generally not worth the trouble.  I just got the feeling from my last session.  She had a higher hourly rate than most girls so I only booked an hour.  She didn't seem that into it even from the start.

Anyway, I usually try to book 90/2hr sessions as I can.  For nights on the town, I just don't want to chance it (especially during conventions) since I don't want to run into anyone I know.