My HR21-100 has been acting up lately (had to pull the plug twice tonight as it became completely unresponsive), so it's gotten me to thinking about replacing it with an HR24. I checked out Solid Signal and they list the -500 model and also a "DIRECTV HR24 High Definition DIRECTV PLUS MPEG-4 DVR (HR24) Commercial HD DVR." Also, Doug's firmware site lists an HR24-100 and -200 in addition the the -500. I had thought the -500 was the only one available, or am I incorrect? I assume the -100 and -200 will be the same basic unit just different manufacturers like all the other HR2x models, but what is the "Commercial" model listed on Solid Signal? It's listed for the same price as the -500? Is it just a typo on their part? Thanks.