The nemesis you have is known by many to be one of the hardest hitting high end mechanical mods out there and it's silver contacts are plated and replacing them is easy and relatively inexpensive. The maintenance required for silver contacts (plated or solid) is really just to periodically buff them out to remove built up gunk which will reduce their conductivity resulting in weaker performance. I have seen solid nemesis contacts sold for around $30 each but they're pretty hard to come by. I prefer silver or gold contacts to copper or brass.
There are many fanboys of every modder. It boils down to what your preference is. Side button, bottom button, VV, VW - DNA20, price, hybrid, etc.
Personally, right now I own a nemesis, 69, roller and provari mini which I haven't been using and I have a futura pre-ordered and due to ship next week hopefully. Sometimes, I get sick of the bottom button and use one of my telescopics but when I feel like I really need a good ... kicking vape I go back to the nemesis. I guess I'm an atmomixani fanboy these days but only after ample research and review of various reviews. He is coming out with 2 new mods hopefully around January. A mini more slender nemesis and a telescopic nemesis AND a revolutionary RDA either later this month or in December - but that's not helping you in your search for a different mod any.
I've seen good reviews of poldiacs and if you don't mind dropping $eriou$ chedder & you can find one, markbugs devices are considered by many to be top notch.
Personally, since you already have a nice high end mechanical rather than getting another which may have a higher resistance perhaps consider getting a DNA20 mod. There are many box versions out there and several tubes (those that come to mind are the wizard evolved & apprentice, cyborg, elevator, and futura).
