>>6772749My opinions here are based on currently owning MMC Backdraft, Maketoys Wrestle, and Masterpiece Artfire (I wanted to have 1 of each offering in my collection).
I would say currently on a pure cost analysis, go with Girder; he can be had for $60 from TFS. The QC issue which Backdraft has, where his front skirting doesn't peg into his waist, I believe was fixed when they did Girder. I won't speak for certainty, but that's what I thought I remember reading. The other main issue I've had with Backdraft is that he just doesn't want to hold his gun well. Or rather, he holds it better in his left than he does in his right. I haven't noticed any glaring issues thus far with Wrestle.
Girder would also be the most compact out of 3 -- there's just about nothing happening for a waist, only to serve connecting the legs to the torso. You can see from your own photo there that Wrestle is larger. Also that his smoked windows do more for his head than MMC's clear windows. I would say he's 1st in terms of transformation complexity, with MMC following 2nd.
This was my poor attempt at a group photo a couple months ago.