Loaded question, brother.
You'll get as many answers as there are mods available. My own opinion? Ive got an IPV mini and a K-simar 20 tube-style mod. I like it on both for different reasons but the vape quality to my own tastes are with the k-simar 20. Most people are going to say that it's underpowered at 20 watts max but I don't go over 18 anyway on that tank.
There are excellent hands on reviews from real people in the APV-VV section here. Flavour of the week seems to be Cloupor mini... it's really nice and cheap too. if you have the budget maybe the SX mini/yihi mod. Do a bunch of reading and looking at pics there. All of them have had issues, all of them have had good reviews. Make sure of your warranty before buying. You don't need 50 watts with that tank. It works well at lower watts than others. .... Enjoy.