[m463]

I'm sure there are modest situations where something that can lift 650 times it's weight is more valuable than the thermal limitations. Or maybe super-cold environments?

[yomly]

Indeed - the cooling requirements of maglev don't seem to have prohibited it from existing

[Tossrock]

Pneumatic air muscles are in the same strength to weight range - for example, the Shadow 30mm version is ~470 minimum. They can also be simply manufactured today, cycle very quickly, and are easy to control.

[deepnotderp]

Pneumatic actuation is also very powerful, and has been used for a while in rockets and are relatively reliable, even in various extreme conditions.