I wouldn't have a diamond cut rim on any of my cars... Unless...
They are factory fresh wheels i.e. a refurb company has not done the diamond cutting/powder coating. Most of these wheel refurb companies won't entertain the idea of a warranty with diamond cut wheels. Thats just down the fact diamond cut wheels WILL get white worm very quickly. They are so so delicate and on the wheels its asking for trouble.
Now, on some factory finished wheels from the likes of BBS/speedline etc... they are doing thousands of wheels at a time which changes the landscape of the plant they're painting them in. They have a much better environment to be painting wheels in, and with that comes much higher quality finishes. Thats my idea on why BBS/ OEM diamond cut wheels last 3-4 years without white worm rather than 3 months to 18 months you'd normally see a refurbished diamond cut wheel lasting without white worm.
If a customer comes to me and asks for diamond cut wheels, I always explain this and tell them there is no warranty. 8 times out of 10 they will do for a full powered coat or wet paint finish. ;)