MVP 3 Pro or Sigelei 150?
Might be an obvious answer, but innokin always has great quality "mods", thats why its hard to choose Sigelei without knowing there quality in products
The MVP is a decent mod tbh, have owned both a V1 and a V2, the extra watts in the V3 is a appeasing, the Pro version the extra watts and extra battery for it are good points, downside is the internal batteries.
Sigelei, I own the Sigelei Mini (30w) and the Sigelei 150, both perform well for what I use them for, the Mini for my RTAs, the 150 for my RDAs. Both require external batteries which is a plus in my book, battery low, pop a fresh recharged battery in, back to running and gunning. On the 150watt though, over 70watts, you'll need to use Sony VTC4s, Xtar XT-VTC4s, LG HB6 30amp batteries in married pairs, mated batteries for the Sig 150, bought together, charged together, used together, never use with other batteries or alone, same would also apply to the 100watt with batteries.
Each brand has their strengths and weaknesses, just have to ask what features you want, and what price point you can afford, in truth personally at this time, I'd look at the Innokin Coolfire IV over the MVP 3.0 or 3.0Pro