I have had the TK16 2.0 for a few days now and am generally pleased. The light pattern is extremely bright and even on the turbo mode it presents the sort of intense, not-too-warm white I prefer. This is the brightest flashlight (yet) that I have owned and it gets warm quickly at the front barrel but not unexpectedly so. I wish there were a ~1-5 lm mode but that is a small nitpick. I also bought the diffuser for this model and can say that it does not seem to fit confidently. I wish there were a red LED but otherwise I'm happy as a peach. In particular I like how lightweight this flashlight is with battery.
The cell is my first with an integrated USB charger and I am unexpectedly surprised by how much I like it. This may be in part because I am a big fan of USB type C connectors which in my opinion is very well-suited to the cell. I have discharged the battery within the light and fully recharged via USB type C twice now, and it works very well with my many, many, many run of the mill phone and laptop chargers. USB battery packs also charge it up just fine. I love the flexibility. As someone who has been involved in battery design for 15 years, I understand all the conceptual and architectural hangups that come with embedded charging circuitry; nevertheless I really like the trend from the user experience perspective.