there are so many styles of trike now, that finding *the best* at something is very subjective. for example, I rode an Anthrotech trike for many years, doing long distance touring for weeks at a time (+1000 km / +600 miles). I found the seat position, track, and wide cargo rack great for touring or daily commuting. Other see the Anthrotech differently, or prefer another style (I'm keen on Steintrikes lately, for example).
Probably the best way is to try as many different trikes as you can get your hands on, try to rent them for a weekend or at least a long day in the saddle (50 miles or more), *then* start narrowing down that list to the top 2-3 that you really feel comfortable with.
Go back and give those another ride (even a short "around the block" test) and ask lots of questions (even to yourself based on your own observations), such as: how easy is it to get in and out of, how stable under load does it feel, is the local bike repair/dealer shop able to service the trike if you are not mechanically inclined, can you make basic repairs easily (flat tire, broke chain, etc.), and so on.
Don't buy until you are reasonably satisfied!