I did the same research last year looking at hiring aircraft after I passed my ppl at Cranfield.
Turweston is great, they are a nice bunch of people and there's the opportunity of the odd fly out, more of a relaxed club atmosphere there.
I visited Sywell, had to admit I didn't get a great vibe, was told the AT-3s weren't for hire and they didn't seem keen to want to encourage me further.
Other places to think about are Henlow, I've heard good things there and also Modern Air at Fowlmere have a few nice PA28-181s. They're at the top end of the price scale to hire but they are lovely aircraft.
I'm back at Cranfield doing an IMC there now, there's no shortage of hire options there, best to look at them all