Xvive U2 Wireless "Guitar" system:
This is a 24bit digital 2.4Ghz (ISM unlicensed) 4 channel system comprising physically identical 1/4" jack "Bugs" with fully articulated angled joints. More details here:
The system is supplied in a sturdy foam lined cardboard case which would stand a gentle life on the road assisted by occasional gaffer tape repairs, but you may well easily store them in your case as they measure just 75 x 45mm when folded.
The units are well designed and finished and appear as robust as can be expected for a lightweight plastic product, there should be no reason for breakage in normal use for the transmitter, likewise the receiver if plugged into an amp or desk. However if the receiver is plugged into a floor pedalboard then it will require some protection if there is any chance of it being "stomped" on. The switches and the articulated joint all appear robust but only continued use will tell. The units charge via USB mini - A USB A-Type to twin USB mini cable is supplied. Tested battery life is in excess of the 5 hours quoted, recharge time is about 1.5 Hours from a USB2 Socket.
Sound quality is quite simply perfect - no degradation, the same as the Line 6 products that I have been using for many years. I have taken it to 100ft (30m) with no drop outs, which is way beyond anything practical in a live band situation. latency is quoted at <6ms - I will check this but certainly no problems could be heard.
The only intermittent problem that I found, but have now solved on my active Sonic Violin range, is a low level, high frequency (2kHz) interference with some orientations of the transmitter. This noise was getting into the pre-amp through the power leads, re-routing them inside the instrument helps as does adding a grounded shield to the leads. This problem will exist on all active instruments and will be dependant on internal configurations, A Yamahaha (comparison demo) electric violin I tested was found to exhibit the noise, a solution for that may be hard to find with all the on board circuitry.
I will take the system on a gig to double check the interference when in typical stage and PA environment but I don't foresee any problems and will most likely be recommending this product, especially considering its £125 Price Tag.
I have done more than a dozen gigs now with this system and had no audible issues. My bass player is also using one with similar success. The lack of dual diversity does not seem to be an issue, but that would be my one potential concern and if you are playing a high value, high pressure gig where any chance of a drop out would be devastating then maybe a licenced, dual diversity, fully encode (bolts and braces) solution would be advisable, but that goes for other more expensive unlicensed systems too.