I agree that it has its ups and downs. It's definitely a fan production, so you can't expect professional quality at every level. Still, as you've noticed, they've done well enough that professionals have decided to become involved. There are frequent cast changes, due to various personal commitments. They've gone through two or three each for Chekov, Uhura, Sulu, and Spock. So, that can be disorienting. I would say that the overall quality of the acting is "okay." Some are good, some aren't very convincing.
The sets and props are great, the photography is pretty good, and the editing is decent. The scripts have generally also been decent. The VFX is generally good. Sometimes, it's outright excellent. Occasionally it's poor, especially in the earlier episodes. The SFX and music are also good.
So, if you're interested in fan productions, by all means give it a shot. For the most part, they're done episodically rather than with story arcs. So, it doesn't make a great deal of difference what you watch first. Just don't start with Blood and Fire, Part 2. The latest, Enemy: Starfleet! also references Blood and Fire. Not to a great degree, but it has what would be considered a major spoiler to Blood and Fire.
Personally, I recommend the episodes with George Takei (World Enough and Time) and Walter Koenig (To Serve All My Days).
