Is there any particular reason not to use a standard propane camp stove? You can get a decent one for a lot less than the (nice) Atwood you list, especially once you add in a base and a propane connection, and the camp stove is likely to be more portable. Even the $20 ones at Wal-Mart or wherever work acceptably well, though they may not be the most robust for hard use. If you get a two-burner model, you should be able to ditch the regulator and connect it to your RV's propane system and regulator should you so desire using the usual grill quick-connects (and appropriate hoses, connectors, etc.). This doesn't work so well with stoves or grills that have the control knob built into the regulator as a single unit, typical of single burner ones.
Once very real problem you'll almost certainly encounter with the cooktop you mention is wind and breezes affecting the flame. There's a lot less wind inside the RV kitchen. Camp stoves often have side and back flaps to help combat this.