It's very true that there are some very ropey and badly set up examples out there, but there's also some really great cars.
you DEFINATELY pay a significant premium for a caterham, but they are generally considered to have the best chassis out there.
What I bought was a factory built Tiger R6. I'm sure many will disagree, but it's considered by many to be the best chassis after a caterham.
Mine had a 2L Zetec on twin 45s (i wanted the noise


Awesome car (Thinforth saw it once) but i got a new (apart from drivetrain which was reconditioned) car. V light, Carbon fibre bodywork, 165bhp and (purely in my humble opinion) the best looking "7" out there, and it only cost me £13K new. sold it after 2 years for £9K (at the wrong time of year).
You'd get much less depreciation on a Caterham. It'd be much easier to sell a caterham, but as i say, you do pay a premium. On the track i honestly don't think there'd be much in it.
Also - how tall are you?? - I've had mates up to 6'3" driving the tiger.
A.