I have to preface this with the fact that I don't do any "real" racing anymore. I do lots of timed centuries, double centuries, slug-fests with my buddies, and hill climbing. To be honest, I just don't care much about alleged aero advantages when it comes to minor frame changes. Sure, TT bikes are better at their discipline than road bikes, but I think the velcro on my gloves comes loose when I'm riding sometimes, my jersey has wrinkles in it, those stupid boa dials stick out of my shoes. I haven't tested my position in a wind tunnel, and, oh yeah, and I'm usually drafting the biggest, fast guy I can find (unless I'm on a climb, when they disappear). I think all of those things could add up to way more than the frame drag. Give me something super-light, super-handling, and super-comfortable, and I'm pretty sure my performance will be better, even if it's placebo effect. In fact, the placebo effect of the aero frame is probably worth it to people who buy them (just not me). That said, if I can have all of the above, I'll buy it.
This! I couldn't be happier with my neilpryde bura sl. No regrets. That said I did ride a cr1sl followed by an addict sl and I loved both of those framesets (but not as much as my bura!)