^^ I haven't heard the Nevatons, but in $1000 range small mics, I think the 406x series are pretty hard to "upgrade."
When and if I'm in the market for omnis again, I'll go to Schoeps mk2 caps or DPA 405x, both of which are larger in size and substantially more expensive.
You could also try the Countryman B3 (substantially less expensive; some prefer them) or the Audix 1280s with Church active cables. The Audix have the advantage of being small and allowing for switchable caps. I have not heard the omni caps, though.