Welcome. Like Tazz said, the first thing to think about is your budget. If your looking for a mid priced variable with a bit more punch then the Smok alien was one of my favourites.
If your looking for something higher up the market then the Yihi SXMini Q Mini was my all time favourite. Also it depends on whether you are looking for something with all the bells and whistles like a colour screen, time, wallpapers, etc.
There’s a lot of choice out there nowadays and my recommendations may already be out of date but post your requirements and someone with far more knowledge than me will be able to help.