I don't have MAP Tank but I do use CE2 Clearos in a DCT, Arry and Torpedo Tank. I've also have a V1 and V2.5 Vivi Nova.
IMO the Vivi V1 was decent at best. Never got any dry hits from it but the flavor was muted no matter what I tried, rebuilding the coil and wick, modding the gasket, widening the wick slot, nothing helped. Comparing the V1 against a CE2 in a tank, well there is no comparison, go with the CE2/Tank combo.
The Vivi V2.5 was a very pleasant surprise, it's been awesome since the first vape, consistent and great flavor. I haven't modded or replaced the coil yet, don't need to. It hasn't leaked a drop, no gurgling from condensation or liquid getting in the center tube, wicks great as long as it's tilted when the tank starts getting low but that goes for just about all the fillerless types. The performance is comparable to my CE2/Tank combos and it's easier to clean and fill.
Hope that helps