I'm most pleased with the Monster HTS-3500's that I have and have modded.
I took out the stranded aluminum wiring I found in mine & replaced it with solid copper (just used Romex). Then I took out the cheap, sloppy outlets and replaced them with either 20A Hospital grade or 20A Industrial grade outlets. The Hospital grade outlets are a little better than the Industrial grade ones. So someday I'll pull the Industrial grade outlets out and slap Hospital grades in.
I've found that the modded HTS-3500 is just as good as some much more expensive models in my particular setup.
I
would not reccommend the HTS-5000 though. It's a picky unit and frequently craps out and needs to be sent back to the factory for repai/reconditioning. Don't know why the HTS-5000 is like that when the HTS-3500/HTS-2500 don't have that problem...
