There are 3 things to know about this light.
The first thing to note is that there is no way to cycle to the strobe option if you choose not to use the remote. There is a button on the side of the light and it only allows you to cycle through the 3 brightness options. The MagicShine website does not mention this at all.
The second thing is that the light does not come with an adapter to attach it to your standard bike computer mount. Instead, it ships with an entire mount of its own. This isn't a dealbreaker by any means, but if you purchased it hoping to attach it straight onto your Garmin mount or whatever, you'll need to purchase a GoPro style adapter which wasn't obvious.
The last thing to keep in mind is that the battery life is not great. MagicShine's website says 2.5 hours on max brightness and I think that is questionable. I typically average a 2 hour + ride so I'm almost always riding on the lowest setting unless I'm on a section of a route where I would expect to see some bumps/debris. If I happen to forget to charge the light after a ride well I'm basically screwed the next night I try to go out.
All that being said it's a decent light and MagicShine does have other decent lights out there too. My rear light I'm very happy with.
I commute in Seattle a couple days a week year around and bought this 15 months ago with the hope of being able to take the round-about way home when its not raining. However, the battery life even on the 100 lumen economy mode was just over 3 hours instead of the 10 hours advertised when new and now it's down to closer to 2 hours so I need to pack my old headlight as a backup if I want to get in some extra miles. When I do need the full power on unlit gravel trails, it does a great job lighting things up but that kills the battery very quickly. If you don't mind charging often, it's a fine light but don't expect to be out too long after dark.
I've been using Garmin products for a long time. My previous bike computer was an old Edge 130 and after I purchased an Instinct watch I moved over to it for most of my training. Recently I got more serious about my training and needed a better computer to follow the workouts I was creating and doing, so I moved up to the 840. It's more bells and whistles than I really need and the settings have some features that default to 'On' that I'd rather configure for myself. E.g., "Why does it keep beeping at me every time I reach the east end of the velodrome? Oh, it thinks I'm about to cross I-75!" I've created a 'Velodrome' activity specifically for my track sessions. And when I'm riding on the road I don't need it to switch the display to a map and show me the grade that's approaching. I'm sure that as I use it more, and take the time to configure it to my particular preferences, I'll be happier with it. But I'm sure that once I do, I'll only be using about a third of all the features it provides.
Long time road rider. I have worn out the battery on 3 varia units, much quicker than the head unit battery. The battery charge lasts through a couple of long rides, same as Garmin. I am hoping, but don't know, if it will do better than the varia at holding that charge 2 years from now. My hope is based on a newer design and electronics. The mount is sturdy, and easier to secure to the seat post. Some of the features are controlled through a separate app, although you won't need to use the app after initial set up. Radar function works as well as the Garmin, and there are more flash patterns, the light turns off if there are no cars detected, and it has a brake light function.
