STC has certainly suceeded in capturing the TOS feel from the beginning, which is most likely because they are all professionals doing their jobs and are likely getting paid for it (I wouldn´t know where else they spent that KS money for) - that allows them to work on this not only on weekends and vacations. NV/P2 didn´t have that start, I think it started out mostly with amateur, but it slowly gets more and more professional - and it shows.
STC so far has only done "bottle" shows, which are rather easy to do in all resorts. It will interesting to see when they are doing their first "off the ship" show, which according to them should be in the fifth episode.
In regards to actors - Mignona to me is not really convincing - he is trying too hard to mimic Shatner, he does not bring a lot of his own to the role. But I guess that is his choice, and that´s fine. He might to be a bit old to play that part, although he stayed in shape very well

. ST/P2s new actor for the captain tries a different approach, and I like that better. Both actors have the problem that their voice is slightly too high pitched, but there´s nothing that can be done about that.
Both Haberkorn as well as Stacy delivered a great performance in their last episodes, so to me it is a tie on the Spock part.
STCs McCoy is not my cup of tea (both of them) - I liked P2/NVs old doc a lot - I thought he was pretty much perfect. Im not quite sure their new McCoy can hold up, although he did a good job in Mindsifter.
Doohan does a tremendous job, I enjoy watching him in his fathers role. Almost as good is NV/P2s Charles Root, so a tie again.
The rest of the cast is pretty much ok in both shows, but they, like the original, have the problem of not getting a lot of screen time.
Certain aspects they included, like the Holodeck or the Counselor feel somewhat misplaced. I assume the counselor role was created to have Mignonas girlfriend on the show in a more meaningful way. Other than that, I see no reason why it has to be there - it takes away a lot from the McCoy role.
Effects-wise I like the steps NV/P2 does with the new design, which is a completely different approach as STC. They try to do it retro, which does not really work. It does not really look like effects done in the 60s, although it is close. Neither did the retro effects in NVs Mindsifter work for me.
I think there is enough room for both shows, STC being more retro and NV/P2 hopefully exploring new worlds and trying out new ideas, exciting stories.