The Sigelei 150W is a nice device, and has all the power you'll likely ever need. To me, it would be like buying a Porche to drive 1-mile to work every day, though, because I rarely ever need more than 60W Everyone's needs are different, though, and if the price is within your budget, I say snag it! Batteries... never mix different brands, different mAh ratings, different Amp-ratings, or even old/new batteries in a dual-battery mod. Rainbowtears suggested two good batteries, and I absolutely endorse the Samsung 25r! For a 150W box, I might also suggest Purple Efest 2500mAh, 35A batteries. Whichever you get, always purchase at least twice as many as you need! Your mod takes 2, so I'd suggest buying 4 or 6, so you will always have a pair ready to swap-out. Also label them in pairs A-A, B-B, C-C, etc. so you can always keep a matched pair together. They'll last longer and perform better that way, IMO.