I don't write reviews on TV shows often (never actually), but given how rejective most comments are toward seasons 6+, i felt the need to throw in my few cents.

The show has some better seasons and some worse, but it definitely never gets anywhere near unwatchable threshold. There are a few inconsistencies after the season 5 that probably happened as a consequence of prolonged story, that is true, but most of them are minor and can be explained as a result of story events happening during these seasons. I was expecting this huge mind-blowing crap that everyone is talking about in almost every review and maybe if i didn't read reviews here prior to watching the show, I wouldn't notice anything wrong with the show at all.

Most seasons have a bit different tempo and the tone. Some are dark, some a lot more positive, some are more action-packed, some are more about characters and their backgrounds, even enemies change and evolve, so yes, season 1 is completely different show compared to season 5 and that is different compared to season 10 or others, but it actually keeps things fresh and entertaining. It might be bad for die-hard fans, but it is more then acceptable for me as a TV shows lover.

Only advice I can give you is not to think about this show as about a Sam/Dead biography (as it seems a lot of people complaining about character development do), but think about it as about a comic series, where every episode is a prep work for usually at least decent grand finale boss fight at the end - the good guys vs. [insert seasonal villain name] vol. X kind of stuff. Try to watch the season 6+ to see it yourself, it has its charm and gets better the longer you watch it.