This is quite a tall order, as you get to know what you like by trying bikes. I'm fairly new to recumbents, about 2 years now, but I can give you my experience.
A couple of years ago I bought an Iowa Linear LWB because my lowish offer on a fairly local sale was accepted. I'd never had a chance to ride a recumbent before and it was a steep learning curve, but I came to like it a lot. It's an aluminium framed tourer with under seat steering, a 20" front and 700C rear. There are no chain tubes or tensioners apart from the rear derailleur. It's extremely adjustable, the previous owner being a lot bigger than me, but as the seat, steering block and bottom bracket block are all adjustable it can be made to fit just about anyone. It's a good feeling piloting this 88" long thing through narrow gaps and turning round in narrow lanes. I probably had a happy accident here, as the main issue with many recumbents is that they are likely to be too big for me. I've had issues getting an upright bike that fitted well in the past, and in the limited recumbent market that applies with knobs on. I would like to try one of the current Linears with disc brakes, but doubt that there are any in the UK.
I fancied trying a SWB and last year acquired a Dawes Low Rider. Well, it was certainly low, but my erroneous assumption that a low seat would equal a boom length adjustable for shorties bit me in the backside. By fitting shorter cranks and using a kneeling mat on the seat back it's manageable but it's not given me the confidence to ride it the distances I've done on the Linear. It rides well, is very manoevreable with no heel strike issues and the roller brakes give good braking with the weight distribution being well balanced between the two wheels. It has chain tubes which feel rather draggy and noisy compared to the near silence of the Linear, plus a tensioner. On balance, though it feels stable at speed, the LWB feels more planted. Perhaps this is due to my personal bias towards under seat steering, but the riser bars on this bike didn't inspire me until I fitted a set of Humpert Englischer bars which feel really good by comparison.
At the end of last year I had the opportunity to buy a recumbent delta trike, something which I hadn't planned. It's a Sinner Comfort in a very small frame size which happens to fit me. I sat on it, the under seat steering fell to hand and after a bit of time convincing myself, it just had to be. I rationalised that when I eventually get too decrepit to ride my bikes, I could still ride this. Not strictly relevant to building your own bike, too many wheels, but it just shows how one aspect, in this case the under seat steering, can make or break how a bike feels.
So, take your pick, LWB, SWB, USS, OSS, rear wheel drive, front wheel drive. It just might be worth taking the plunge if you are of average height to buy something cheap and cheerful and see how you get on with it before diving in and making something yourself.
