I've been playing for years and my two mains are a Grand & an Ultimate. Grand is my favorite(because I put the most time into it)
If you want to
solo pvp do not choose Grand. I REPEAT if you plan on doing
solo pvp do NOT pick grand.
For PVP & PVE I recommend Ultimate because people aren't use to & don't understand grand majin so before doing any kind of group activity they would choose an ultimate over a grand.
Don't get me wrong..Grand Majin buffs are on par with Ultimates buffs but most people in DBO don't realize that & don't want to chance running CC71 with the ticket they paid an arm and a leg for using buffs they're not to sure of.
Ironically Grands excel in party activites more than Ultimate Majins...but to bad nobody wants them.
Also you need to gear the fuck out of Grand.
Ultimates aren't as needy as Grands so you'll have a much smoother time playing one. Grand Majin is just so complex
By the way the level 70 update nerfed Grand Majins so terribly bad. It's like comparing a SK to a DW when it comes to tanking..It's arguable whose better but SK will win everytime.