Does anyone have any experience with Rosen OWB holsters?. I know they are expensive..but how are they in quality etc?.

Really no better than some of the other custom makers that are a little less expensive, and Rosen's customer service leaves a bit to be desired.  Try Sparks, Alessi, or DelFatti, you'll be pleased and they are great people to work with.

IMO Mitch Rosen holsters have Excellent quality. I know that the 5JR is very popular.

I'm sure they're as good as the other top leather makers out there, but seem to be a bit more.  Ordered my first Rosen holster recently, 5JR as a matter of fact.  

Milt Sparks is also excellent qualty. For OWB, I mostly use the I-BAK for the Sig 239, 229 and 226.
And the MS Belt..

Quality is top notch. You get what you pay for. Everytime I've bought some other brand I always end up comparing it to Mitch Rosen. I have 3 ARG IWB holsters, 2 Belts, a single mag pouch, and 2 SOS mag/light pouches. One of the SOS's has been worn everyday for 10 years. His express line products are what some other makers wish they could make in their best quality items. Don't get me wrong there are other quality holster makers out there. Sparks, Ted Blocker , Tauris Holsters, to name a few.