From those 2, I'd get the Reuleaux. They both have all the TC modes (Ni/Ti/SS), both USB Firmware upgradable, both "200W" (Cuboid 200W Pulse/Reuleaux 200W Continuous). I've held both and they both feel great, but I feel the Reuleaux is more ergonomic (Different form factor compared to the common box shape), more stable while standing (wider stance), has nicer buttons (IMO), has a nicer battery bay (Cuboid battery door/latch is finicky, especially without batteries installed), feels more solid (The cuboid doesn't feel cheap, but I prefer the weight of the Reuleaux, don't like things feeling light, it just feels more durable), and is a triple 18650 (so longer battery life under the same load)
Another plus for the Reuleaux is the already large user base. There's tons of people with this mod, and a lot of user feedback/information available about it, so if something did happen, there's readily available data and experienced users to assist you with troubleshooting.
As to the battery issue, it's highly recommended to never use the USB for charging if it can be avoided. It's a safer bet to use an external charger, not to mention it'll charge a whole lot quicker too. Most mods with removable batteries have run into USB charging issues at one time or another, it's a rather common occurrence, even with a Evic VTC Mini.
On a side note, I've heard a few people say they found their Cuboids Voltage Cut-Off to be finicky, some would cut off at 3.7V, others at the normal 3.4V, and then I heard a case where one wasn't cutting off until 3.2V. I have no actual data or reference point to back up these claims, but it would make me leery to buy one.
When all is said and done, both mods can perform well, so it all comes down to personal preference. A few questions I ask myself when deciding on mods:
-Would I be willing to carry this around all day?
-Would the battery life be enough for my needs? (for mods with built in batteries)
-Would I be willing to carry extra batteries? (for mods with interchangeable batteries)
