I'm running this in Vincent Lee, 4 player, Forgotten Age run with Guardians of the Abyss as a side scenario. I went in with modest expectations, and Microscope met those expectations.
Microscope promises to let you spend 2 actions for 3 clues, and only 1 test which you will take at +2 or +3. This is quite a lot for one card to do.
In return, there are hoops. You need to collect evidence by dealing with monsters. You want to spend 2 at a time, but can only gain 1 per round. Overall I hope for about 9 clues for 7 actions and 2 resources, with good bonuses. Even 6 clues for 5 actions isn't terrible, and it comes with the upside that if you do somehow fail the boosted investigate, you at least keep the evidence.
My overall rating of this card is... it's fun! It's fun getting evidence when you or a buddy deals with a monster. It's fun getting a big clue turn on your usually more humble investigator. The card is well balanced and serviceable and I recommend trying it.
The obvious comparison would be Fingerprint Kit, which costs 2 more to play, but can net you 8 clues over 5 actions, with a smaller skill boost. Fingerprint Kit also doesn't require you to keep it out for the entirety of the game to get it's max benefit, or find 2 turns during your turn to get extra clues instead of 1.