Is 我的中文水平还是挺有限的 a suitable translation of "My Chinese is still quite limited"?
我的中文水平还是挺有限的。 (My Chinese level is still quite limited)

Nothing wrong with 水平有限 (level is limited) in which '有限' suggests 'not advanced', 'cannot be considered good'
Any adjective that can describe 水平 (level) would do. You can say:
我的中文水平还是挺低的。 (My Chinese level is still quite low)
我的中文水平还是挺一般的。  (My Chinese level is still quite ordinary)
Notice: while 差 (inferior) can describe level, (as in 水平很差),  不好 (not good) or 壞 (bad) cannot. We don't say 水平不好 or 水平壞 because they are not a measurement of level
Side note:
In Cantonese, we have common expressions like 好人有限 (is not that good a person = is a bad person); 好打有限 (is not that good at fighting = bad at fighting - a metaphor for 'not very capable' which can be applied in any area)