I like Fenix and have a couple of their flashlights... not this bike light. Don't think about using the 2 brightest modes.. light with get hot really quickly.
About 350 lumens is enough. This light looks good but maybe overkill, and it will add more than 3/4 pound to your bike. Light itself 6 oz. Separate battery back weight unknown.
Light and Motion Urban 800 fast charge... enough for 3 hours of riding.
You will get many opinions on personal bike lights.
I know user @RR3 said they had the BT20R (the 20 not the 30) and they really liked it, led color output was fantastic (not the cold blue/purple that a lot of LED's have) and it goes way down the road. Haven't used it myself though.