Been running a Moon Shield for around a year now – USB rechargeable, super bright, neat and compact with rubber mountain strap gizmo. Only issues are that the USB port cover is held on by a very thin bit of rubber that inevitably breaks with use after which it needs lots of care not to lose it when charging and the battery only holds charge for a day or so, so you need to charge it up regularly.
Also just bought a tarty Lezyne Micro Drive rear light for the road bike, which I’m quite impressed by initially. Again bright, USB chargeable, very neat with rubberised seatpost mounting for easy bike swaps. It’s a snap fit into the mounting bracket which looks slightly precarious, but it’s very positive and I’ve added a thick rubber o-ring just in case, but tbh, I think you’d have to try hard to lose it.
And I still have a Holy Hand Grenade sat around which I use occasionally.
Mostly ride unlit roads, but bright flashing rear lights also work well on wide, fast A-roads during the day, you just seem to get a little more space.