Lots of good replies already, but here's my tuppenceworth.
I started building and riding bents about 2 years ago. Five home build projects later and one "real bent" (Metaphysic) I have now clocked up something like 6000+ km, of which a 1450km and 3400km touring trip with tent etc. My personal experience is that I can't climb as fast as on my DF road bike, but I'm not that far off. But I can climb even very steep hills (including the french Col du Tourmalet with luggage) as long as I don't mind spinning away at 7 or 8km/h. At these speeds it can get a bit wobbly to keep on line, so good concentration is required. I also find that the nature of the steering makes a big difference to handling at these low speeds. The "hamster" bars give a noticeable "tiller effect" which can make the bike twitchy, while the "open cockpit" bars allow the arms to be more or less straight and makes for less sensitive handling. The same bike with different handlebar configurations can feel completely different to ride.
On the road I often find myself with a huge grin and shouting to the wind "this is so f***ing good!!!" I have never done that on a DF bike, even when I'm really enjoying myself.
For me personally, I am never going to break any world records, so the main plusses of a bent are:
1 - comfort over long distances; literally no aches and pains anywhere (aside from legs!) even after 7+ hours of riding
2 - brilliant all round vision; on an upright bike I find myself with my head lowered, looking at the road in front of my wheel. On my bents I can power away at full tilt and still have a perfect all round view of the countryside I'm riding through.
On the downside, I don't feel that my bents are "urban friendly", and I try to avoid built up areas and in-town traffic. For me, the problem is that it is often necessary to ride slowly between or around cars, with sudden stop/starts. I find such slow speed slaloming quite tricky, and if you stop in the wrong gear it's much more difficult - even impossible - to start off again because you can't get out of the saddle and heave on the pedals to get momentum as you can on an upright.
In terms of choosing a bent bike for a newbie, I'd say that the lower the pedals are compared to the seat height the easier it is to control at low speeds and to start off. A low seat helps too because you can easily get a foot down when stopping. However, such low pedal, low seat designs are not the best for fast out-of-town riding. I'd suggest to a newbie to try to borrow or rent an "easy" bike for a few days to get the hang of riding a bent, and then choose a more "advanced" model for evolving from a beginner to an "intermediate" rider. There are so many different types of bent out there, the best is to try as many as possible (or, at least, as many different types - low racer, mid racer, hi racer, FWD, RWD, SWB, LWB...) before splashing out a lot of money.
I have no experience of trikes, but I would make the following observations: 1 - yes, you can ride very very slowly uphill, but what fun is that; 2 - they are generally very low, which means visibility to other traffic is more of an issue; 3 - going round bends very fast (e.g. the very fast descents on those steep hills that you climbed very slowly) can be tricky cos you can't lean like a bike; 4 - one or two models fold up, but try getting a non-folding trike on a car bike rack!
Whatever bent you get, enjoy it!!!
does not make for relaxed riding - 'bent or DF ... 
... but it's less distance to fall on a 'bent ! 
My record is 47.8mph by gps... there was a spike just after of 51.2 but I don't believe it... I wonder if there is a strava section for that piece of road?
