I have had my Sigelei 30w for some time, and I have little negative to say about it. It is small, sturdy and had lasted numerous tumbles. It has a magnetic door on the battery slot which is convenient, and 5 programmable wattages. It comes with a silicon sleeve for extra protection which is a plus. This review is short but there isn’t too much to say. Sigelei makes quality stuff and this item is no different. Some will no doubt find 30w underpowered, but it fits my bill perfectly. The one negative I can think of is the positive pin in the battery compartment will tarnish eventually and you may lose your power connection, clean it appropriately and you’re back in business.
Update: (Dec 2015) After one tumble too many my Sigelei 30w has died. The 510 connections stripped so nothing will screw in anymore, perhaps a design flaw.