I have one on my .270. No issues with it.
At the end of a days shooting, give the internals a good spray with WD40 and leave it standing in the gun cabinet on a few bits of kitchen roll to soak up any WD40 that runs out the bottom.
I have a JD224 for a 6.5x55 on my .223 and I'm very happy. Very light and excellent sound reduction.
One thing to be aware of is that they need a special tool to open them up for cleaning or whatever, and these can be bought for a few extra bob. The dealer who sold me mine said they practically never need cleaning, and advised me not to bother with the tool, but I got one anyway just to have it there.
I have a SD 228 on my 17 Rem fox rifle, great bit of kit. Bombproof quality, great sound attenuation and truly calibre specific. The manafacturers are nice guys and very customer minded. Dont intend to open/clean any of the various makes of moderator I own.