I went and rode a 19" Specialized Rockhopper Expert 29 and wondering what the pros and cons of the 29" wheels are. The bike felt pretty good overall but maybe a little big. The top tube was maybe 1" or 2" from my crotch. I'm 6'2" and 250 lbs (hence the reason I want to start a more active hobby lol).

The guy said that the bike would roll faster, which is good I think but not sure it fits me right.

Do the 29er's sit higher than the 26er's with the same frame size?

It's just right for your size. I'm your height and I'd ride a 19" as well. Unless you're gonna go nutz and do some tailwhips...then you'll want a 16"

So there's enough clearence? I'm just concerned about the family jewels!

I'm also 6'2", and I ride a 19" 29er. I probably could get away with a 17", too, but the 19" is a bit better reach-wise for me.

I'm not exactly the most skilled rider out there, so I make use of the crotchal clearance on a regular basis. No problems so far...

Just an opinion, you should probably be on the 19, unless you have short legs for a guy who is 6'2". I am 6'4" and ride an xl.
29ers "roll faster" because the larger wheel size reduces approach angle to obstacles. If you have ridden a 26er before, you would probably notice right away.
Some manufacturers 26ers and 29ers will have the same stand over, specy is one of them I think. At least they were when I was shopping.

Thanks. I went with the 19. It feels a little tall but overall very comfortable while riding. The bike feels very fast as well. So far I really like it but haven't had a chance to get out on a trail yet.

I just got a 21. I'm 6'2" and ride mostly fire road, not real technical single-track. I went with the LBS guy's advice (who has been on 29'ers for 8 yrs): move yourself "further back behind the front wheel" to max out the ride on a 29'er.

I had been testing 19's for the last three months and just assumed that was my size. As soon as I got on a 21 the fit seemed better. Who knows - my inseam, flexibility, frame geometry etc. are probably the final determinants anyway.

Riding style too...I hate being all "laid out" like an aero'naut. I'm stoked on my 35mm stem / 2" rise bars...easier for me to lay down suppressive fire on unsuspecting trail chatter.

Keep your feet on the pedals and you won't have to worry about standover.