i have driven LPG cars with no problems and i would have no hesitation in buying one. You just need to make sure its a profesional instalation with a certificate, which i believe is required for it to be exempt from the london congestion charge.
There was certainly no difference in performance between petrol & LPG and as LPG is half the price it equates back to almost double the MPG.The only issue i did have was filling at some pumps could be a bit fiddly just needs a bit of practice.