lower profile makes them useless to sit behind, though
True, assuming the wheelsucker is unwilling to lean over enough to lick his/her front fender 
(CAVEAT: I'm an unusual case, as I went from no cycling to riding 'bents inside of 6 months, so I can't provide good info regarding differences from many uprights.)
With regard to ride, it can be pretty plush; even unsuspended models distribute a lot of the bumps over your back and nether regions evenly, so, while bumps are still perceptible, they don't tend to jar you too much. On the other hand, handling is a bit different; center of gravity is lower, and the front wheel is usually far more lightly loaded.
WRT road safety: I've been hit once in 4 years (overtaken from behind and smacked by passenger-side mirror); the frame of the seat absorbed most of that damage, so I didn't even go over. For the most part, I'm an unusual enough sight that drivers snap out of their business-as-usual hypnotic zone and pay attention to me, if only to identify this bizarre thing on the road. I tend to receive a wider berth on the road than many upright cyclists. Visibility is also a question, as my head is lower than that of most upright riders, but the 'bents I ride on a daily basis have me at roughly eye-level with the driver of your average sedan, so not a big deal.
WRT climbing: well, it's possible to climb almost anything on a 'bent, although I've found that front-wheel liftoff becomes a problem with grades in the 25% + range. What sucks about climbing on a bent is that you don't get to change positions and recruit the muscles differently, so you have to do the same motion over and over again. Think repeated leg presses. That said, low gearing helps, as does spinning rather than mashing; and, on the bright side, you can develop a really nice burst of power by pushing into the seat back for short sprints.
Common wisdom in the 'bent community is that it usually takes 1000-2000 miles on a 'bent before your muscles acclimatize enough that you can ride as well as on your upright. True? I dunno.
If you'd like to try out one of mine, we can work something out; I've got my commuter (RANS Rocket) and my brevet bike (Lighting P-38) available, and, if you demonstrate a lack of incompetence on those, you can even try the Baron lowracer I have on extended loan. (That one we'd have to keep to trails or a park loop, though, as I ain't letting anyone other than me risk their necks in traffic on that twitchy beast.)
Ambridge Bike Shop used to have a few models floating around, as did Rapps in Butler. And Kraynick is good to talk to about such things as well, although he rarely has one in the shop.