Seasons 1 and 2 are excellent with great mysteries and compelling stories. The rest, not so much. After these two seasons, it goes downhill quick. I recommend just watching seasons 1 and 2, and then watching the animated movie "Justice League Flashpoint Paradox" once you finish season 2. Then, just stop there.
The main villains in season 1 and 2 are truly great. The intrigue behind who the villains are, in particular, is extremely engaging. The drama is almost always great. However, the characters do like to keep secrets from each other quite a bit which gets frustrating. Some episodes are clearly just filler and feel like a waste of time. Some of the CGI can also be a little off-putting, but that's to be expected with a TV budget. Overall, 9 out of 10 for seasons 1 and 2. Don't care about the others at all.
The main villains in season 1 and 2 are truly great. The intrigue behind who the villains are, in particular, is extremely engaging. The drama is almost always great. However, the characters do like to keep secrets from each other quite a bit which gets frustrating. Some episodes are clearly just filler and feel like a waste of time. Some of the CGI can also be a little off-putting, but that's to be expected with a TV budget. Overall, 9 out of 10 for seasons 1 and 2. Don't care about the others at all.