Gunpla Grades
Gunpla kits come in different sizes and complexities.
High Grade
My experience started and has predominantly been with the most common grade of Gunpla, the High Grade. Since they are generally cheaper, I feel more free to experiment with them.
There is naturally a lot of variety in design and engineering with this line. I've found the Witch from Mercury kits in particular to be fantastic.
Real Grade
I like the balance that the Real Grades strike between the size of the High Grade and the inner frame and detail of the Master Grade. The designs are some of the best. Unfortunately, there are not many of them.
I disagree with the poor reputation the earlier Real Grade kits have. I've found that nearly every kit will present some sort of challenge.
Master Grade
I've only built one Master Grade so far. I marveled at the creative engineering details on the inner frame. The larger armor parts made working with them and painting much easier.
Super Deformed
The chibi Super Deformed (SD) kits are small and inexpensive. There are several different lines. I've built and painted several Ex-Standard. The front facing details are nice and cute, while the amount of masking and the hollow backs can be a bit frustrating.
I have yet to try the other SD versions. The BB Senshi are older and extra stubby. The Cross Silhouette feature a basic inner frame in two sizes.
Master Grade SD
The MGSD kits are relatively new. They combine the exaggerated proportions of the SD kits with the detail and engineering of modern Master Grade kits. I've built one MGSD so far and it was a ton of fun.
Entry Grade
I've built a couple Entry Grade kits with the family. Overall, they have been nice. The color separation is typically better than high grades. The joint design is simpler, especially in the ankles.
Perfect Grade
I have yet to add a pinnacle of Gunpla into my backlog, let alone build one. The size, cost, and time needed are a bit intimidating.