Depends if your priority is "Masterpiece," or just "really cool." Leonidas is glorious obviously, but he's his very own aesthetic that doesn't match anything from the cartoon. Transistor on the other hand fits 100% with an MP collection, toe-to-toe with Soundwave as he should be. Quality wise KFC has had a couple paint issues, can't speak for Leo.
As an owner of both, I would go hands down with PE Leonidas... that is one of the nicest figures I have ever seen and has the right heft in hand that just gives you perceived quality... Transistor feels like a strong gust of wind can turn him into a kite... Furthermore, Takara will eventually get to Blaster and if you're a G1 purist that needs the official product, you will inevitably need to double dip the way that I unfortunately will have to...
as a standalone collectible? Leonidas to match the MP line? only Transistor Leonidas's aesthetic and design aren't "conventional" Transformers-based.
I want a bit of both. I want close too MP and cool (I consider Xovergen God Armor, Citizen Stack and PE Warden with Add ons as MP), so Leonidas would work. Transistor, would work out well too, but then I know Hasbro will eventually come out with their own MP rendition.
Before you go thinking there won't be an eventual MP Leo Prime, just remember that Takara teased a (rather hilarious) MP Optimus Primal this year. Could be years out, and certainly won't look as cool as Leonidas. But if that's a score against Transistor then it can go both ways... I may be biased though since I just ordered Transistor from the Aliexpress sale this morning. I figure even if Takara does put him out, he won't be as shiny and Transistor looks so damn perfect anyway (though it sounds like I'll have to transform him with extreme care).
True on both, but like MP Magnus- I preferred Stack. And with how the teaser for Primal looks- I dont have the confidence in Has/ Tak to make a Lio Convoy as how I'd like it to be. I trust Has/ Tak to make a better Blaster.