>>9232873At this point, it's hard to say there really is a best because all of them have their pros and cons. For value and money, I would say the model kit just because of the accessories gives it the most current version from the show (aside from the incorrect thigh armor which can be bought third party). He may be big but you can just say it's the stunt guy in the suit. But if you can't paint then it's definitely not the best option.
Mafex looks fantastic proportion wise but it's a gamble with the QC and he's got a pink gun. I personally am going to wait on getting him in hopes that they do a season 2 version and fix some things.
Black Series isn't bad per se but it's the lowest tier out of all of them. If it's your only option, I wouldn't say it's terrible, especially for the price. And if you get a wonky helmet you can always get a better one from third party sellers.
SHF is personally my favorite. I don't think his helmet is as small in person as pictures make it look. When I first got him, I held a Jango headsculpt up to it and it's plausible a human head could fit in there and Din's helmet is narrower than typical Mandalorian buckets anyway. Not saying it isn't smaller than it should be but it's not enough that it bothers me when he's on the shelf with other figures. It does need the neck extension mod to make him look right though and the engineering for the rifle sling is ass so I just leave it off him. Hands down the finish on the armor is the best out of all of them though. Also you get the different shoulder bells to make him an early season 1 version or the other with the signet which is nice and is something the others don't do.