I purchased the Apex Alpha Ultralight because it uses replaceable (protected!) batteries, has an extremely impressive ceramic reservoir that doesn't rely on a wick to transfer liquid to the atomizer, uses cheap and reliable Joye 510 atomizers, has a sweet mechanical switch, and has a very simple all aluminum (except for the switch internals) modular design. The unit comes with a 10 year warrantee (3 for the switch), and the folks that sell it at innovapor.com are really serious about customer service. I chose the ultralight because it's about the smallest mod I've ever seen. I've actually liked it so much that I'm considering buying one of their larger options for at-home use (larger reservoir). Make sure you look around the forum for coupon codes if you're interested. They offer 20% off for forum users, which makes the price (IMO) very reasonable.