Don't judge ECW based on how crap the WWE ECW show was. The original ECW was awesome. Contrary to popular belief, ECW wasn't all about weapons, tables and chairs. Most of the matches were normal wrestling matches. ECW was about wrestlers giving 100% effort in everything they did. So you get great matches and great promos. The stadiums used were small at around 1,400 capacity but you wouldn't think that when watching the show on TV as the crowd was much louder than a WWE crowd and very vocal.
ECW Hardcore TV was good all the way to the end, including the last season. If you're not sure what season to buy, I would start with the last few seasons to see if you like it or not.
Please note that poorer quality yet more expensive sets are available on Highspots.com. The differences are as follows:
Problems with Highspots Versions: Some footage is missing, the episodes are sometimes out of order, they have audio hiss, they look compressed and have a lot of picture noise (grain) and they usually have way too much colour where everyone looks too red or green, etc. Different sections of the same episode can have different colours and brightness! So one match in the same arena could look fine then another match from the same arena (from same house show) could look way too dark.
RareWrestlingVideos Versions: These versions don't have any of the above problems and they are the original TV airings which have the original music and entrance themes unlike the WWE Network versions.