A lot of it is blown out of proportion too because people equate dealer charges with the actual cost to fix it. BMW charges a RIDICULOUS amount of money to do very simple things. If you're able to do your own work, I wouldn't sweat it at all.
The biggest expense I see people complaining about is the HPFP. It's a $300 part and takes under 3 hours to install in your own garage with regular tools. Many other parts are similar. The parts are not expensive, it's the ridiculous labor charges that BMW quotes (most of the time paid for by warranty, etc) that blows it out of proportion.
I spent more in maintenance on my S2000 than I did on my BMW, both with similar miles. S2000 needed a new clutch, BMW hasn't needed a thing except constant cleaning of my wheels because of brake dust
I expect if the HPFP ever goes, I'll still spend less on that than the clutch on my S2000.
'09 E93 M3 6MT, ESS VT2-650, UUC/Corsa, MS X-pipe, H&R sports, Volk TE37SL 18x9.5+22f and 18x11+34r, Spec TwinDisc P-trim, UCP
'09 Z4 sDrive35i, Deep Sea Blue Metallic, DCT, Premium Pkg, Ivory Leather pkg