The PalmPad remote I got today works pretty well.
After doing a lot of reading on this forum I ordered the ACT CR234 today, hoping this will solve my stability issues. My home is 3000+ sqft ...
The 234 is a great unit, as is the XTB IIR. They repeat the PLC code the CM15A puts on the homes power lines and you will need that in the large home.
They will not help you with the poor RF range of the remotes.
Search the forum for "antenna" or "antenna mod". Also search "passive radiator". You will see that you are not the only one with RF range problems. Regardless, you should have better range than " right next to the CM15A". The Palm Pad should give you 20-30 feet, through walls. The range of the SS13 should be similar with new batteries.
Get the CM15A up high. If you home is two story, move the CM15A to the upper floor and check range. You may have a CM15A receiver problem.