You're Gonna Need a Bigger Bat
I will start this comparison by saying I like both versions of this Pokémon but as you can see they are very different.
The biggest talking point here is clearly that both are "Scale World" meaning 1/20 versions of the Pokemon. I believe the BQG is much closer to the correct size.
BQG Size* - 6cm
TH Size* - 3.4cm
*Top of Horn to Bottom of Body
I believe both of these figures have a nice paint application that would give lots of studios a run for their money.
The shading and detail on the trainer house Crobat would probably give TH the edge when it comes to the painting of the wings.
While the BQG Crobat has much simpler paint compared it is still very cleanly down and looks great on a shelf.
Build Quality & Stands
Both figures require assembly with the four wings coming separately on both.
Both are from two of the most talked about studios in the hobby right now and I believe the build quality comes through with both.
The BQG Crobat has magnetized wings meaning they can plug in very easily, the magnets feel very secure. It as has a magnet in the base meaning you don't have to worry about it falling from the base.
The TH, unfortunately, doesn't have magnets but comes with tac and can be inserted very easily and feel very solid once they are in and secured. The stand on TH wraps around the Crobat so that it is solid and the stand shouldn't fall.
If your shelf is starting to fill up with Pokémon TH is likely to be the better choice with its smaller stand and frame but if you want a statement piece that is going to pop on the shelf I would personally go with BQG.
Set & Price
The TH Crobat comes with Zubat and Golbat which convinced me to buy it as I'm currently trying to get one version of every Kanto Pokemon. The Zubat and Golbat are very nice but have very low bases for flying Pokémon.
Price - $115 - Still available here.
The BQG comes with Fuchsia City's gym leader Koga. The Koga is nice and one of the better trainers currently in my collection.
After Market Price - $135 - $160.
RX Studio - $70 - SOLD OUT.
I don't think it's right for me to say one is better than the other here as I believe it comes down to personal preference but I can tell you my thoughts, if I had to own one I would choose BQG as the overall size and build quality gives it a slight edge for me over paint shading and a nice box. If you would like to read reviews of either of these two sets they can be found on the site.