In my 4 years of aero ownership I'd say I've covered 40000 miles. I've had a few niggles but nothing to stop my fun. Touchwood.
Regarding the bills, they probably are higher than a Trad and most DIY activities are out but I don't feel the costs are are out of this world. Before I got my first aero I'd looked at a few TVR but was put off by the bills to keep them going.
I certainly don't regret my choice and I'm not on aero number 2 and I'm you'll feel the same with some more miles under your belt