Bit of an insight in to this one, to compare the V10 to the V8 is like chalk and cheese. I owned a V8 for many years, but I have driven a few V10 ones and they are totally a different kettle of fish. The V10 is a very under-rated car. A lot of people do not realise the engine was build and designed by Williams the Formula One team. This corresponds when BMW and Williams were in Formula One together.
The engines are actually stamped with Williams' name.
They are pretty reliable, the only thing that normally goes at around 40,000 miles is the valve activators which normally cost about £2,000 to replace, but now VW are actually offering repair kits for £150, which are quite easy to fit.
One of the other faults on them was rod bearings but this was normally caused by people reving cold engines. You can get a kit for about £800 I believe.
If you are looking to buy one make sure it has had the factory recalls, SMG pump, factory cable, valve feed, which only really applied to early cars.
It was quite a very technical engine in its day, as the last ones became camless as it was operated by electronics.
Due to costs, I would be surprised if any manufacturers will ever go down this route again, and this car is well underpriced and has to be a future classic.
Don't ask me how I know, because there are going to be some wise people telling me I am wrong, but I know as my son is a BMW technician and works on these on a regular basis.