RDB is a step above the T97 (Gen 3 T97 is around $1300, the RDB is around $1500) - but below the Tavors and X95s ($2600).
Needs some minor work out of the box. Trigger is good. Disassembly is a #####. Gas setting requires fiddling, otherwise you get stovepipes, jams, or failure to ejects (have had bullets pushed into the case, or cases bend by the force of the recoil).
But once you finish loctite'ing the screws, and finding your gas setting, its a fun plinker.
The M17S is supposed to be much simpler, and you can almost take it apart like an AR (uses pins and pivots open). Supposedly has a custom-grade trigger pack which is smooth.
Only thing I've noticed on reviews is the barrel heats up (obviously) during sustained firing, and because the rifle is pretty open and made of metal, the heat comes through and you can feel it.