It's all a matter of preference. I ordered a TerraTrike Cruiser ("Ghidrah", the terror-trike), but just before I picked it up from the shop, I noticed a Sun EZ3-USX listed on Craigslist. Since Jeff would be with me, I thought we'd look at the Sun to see if he'd be interested. He test rode it, and ended up buying it (paying $500). I rode it, and hated it -- but love my TerraTrike.

Here's Ghidrah, a tadpole design:


Here's Jeff on his trike (underseat steering, delta design):


It wasn't easy at first getting in and out of my trike - I've got two total knee replacements and finally figured it out after a half-dozen tries. The Sun is much easier to get on and off of.

BTW - we settled on a trike for Jeff because he hadn't learned to ride a bike as a child, and has developed some equilibrium problems.