>>8241491Difficulty with snapfit model kits comes down to mostly extraneous/time factors for me, the HG/MG kits themselves generally take the same skill level to build just more or less time. If anything the age of a kit will decide more how well engineered (and easy) a kit will be to build.
However with RG and HG, RG has an inner frame like a MG but at 1/144 scale. The size and number of parts/transfers/stickers does make it harder and slower to clean up, paint and handle. I think RG kits are harder and expect more experienced builders, but are significantly better.
If anything HG can be more finicky at 1/144 with MG having a similar number of larger parts. If you follow some guides the MG inner frame makes separating parts out for painting before assembling far easier, and the inclusion of details like waterslides is an easy way to add 'quality' to the build without being a complete fucking nightmare.