Well, what do you like more:
Having all the characters now or can you wait to get a little at a time?
Having Optimus be at a leader scale or voyager scale?
Do you want them to look as G1 as possible or do you like the idea of having them updated?
Because with Classics and Generations, you can get all the popular characters from the G1 show right now. And the scale will be great with Optimus and Megatron as voyagers, and Jetfire as a leader class (so bigger than them). But they wont look as G1 as possible, unlike the MPs.
Now if you go for MP, firstly it will be super costly. Each seeker, is between 100 and 200$. So all six could easily cost you $1000, and thats just the seekers. Are you ok with that?
Also, not all the characters are there. Many, but not all. There is no cyclonus, or arcee, or kup, or jazz, or galvatron, or astrotrain, or blitzwing, or trypticon, or blaster and on and on. All those either exist already in CHUG or will by next year

However, they dont look all G1 and may have extra features you didnt expect. Like a voyager soundwave turns into a truck, Blurr, Galvatron and Scourge have headmaster gimicks.
So its up to you and what you want.
Personally, I collect CHUG and the MPs that I like. For instance, I didnt get all the seekers, but a few instead, just to experience the toy. And I only got Ironhide instead of both him and Ratchet. But thats because I dont need the entire G1 cast in masterpiece scale. Thats just too expensive for me, especially since many of the molds repeat (2 vans, 3 datsun cars, 6 jets).