Congratulations on your purchase. It's the best selling device on the market and will continue to go strong for a very long time. I own five 20 watt and two 30 watt iSticks, all have performed incredibly well and I have no regrets whatsoever. I have the 50 watt on order as well, silver was a good choice. As far as tanks go, the entire Subtank series is excellent and you can't go wrong with any of the three. It will ultimately come down to your spending budget and whether you prefer a 6ml tank with a 25mm base but can be converted to 22mm with the ring or 4.5ml tank with a 22ml base. I enjoy them both. One advantage with the larger Subtank is that you can use your Aerotank coils in it. The mini had improved on their deck and you no longer have to change the top cap to convert into an RBA. You can get them here for a very good price
www.evape.us. Enjoy your silver Istick