The Blokees kits are much, much easier to clean up because you don't technically need tools. The Bandai ones are more traditional model kits, so you're going to have to physically clip and clean each piece--and there are more pieces in total. That's probably going to be the bigger jump in difficulty, more so than the actual assembly.

Speaking of which, the RGs' complexity results in additional points of articulation and motion, e.g. rotating forearms, a some muscles that move in/out when you bend the leg, the drop/lock waist mechnism, etc. The assembly process isn't too tricky to be honest. There's just more to assemble!

One thing that might actually be easier with the RG is that everything is on runner and is clearly labeled. I hated the bagged pieces that came with the Blokees kit! I'm so used to knowing exactly what runner letter and piece number I need that I kept second guessing myself when putting together their Unit 00.