Been FTing for 9+ years with 3 Excel 5th wheels. Had Mor/Ryde install Kodiak disc brakes with Carlisle actuator. Awesome performance and well worth the bucks. Last 2 rigs had factory installed Dexter which work well also. Like already said the parts for the Dexter are limited availability and very expensive $100+ per axle. Kodiak are the 315 series GM pads available at every corner auto parts store and you can get pads for $15 to $60 per axle depending on what you want.
If I had my choices I'd go with the Kodiak. On RV disc brakes if you lose pressure anywhere in the system you don't have brakes. Chance of anything happening like that are very slim. In automotive we started using a split system in the late 70's.....the RV industry is that far behind time. We (automotive) had disc brakes in the 60's (optional). There is a good reason why we went to disc brakes. Get it!!! rockin'