I've been using these for almost eighteen months to power guitar pedals, tuner, metronome, headphone amp, etc. The device among these with the largest current consumption is an FEA compressor (30mA). In all cases the battery will keep the devices running without problem through performances, and rehearsals.
For those used to alkaline batteries, watch out for the discharge curve of NiMH cells; you will not get that slow discharge, and thus plenty of warning before needing to change batteries, that you get with alkaline batteries, and you need to get into the habit of changing, and recharging, batteries preemptively.
Other than that? No memory effect; high capacity cells; reasonably quick charging, etc.
What?s not to like? After 12+ months of use, one of my batteries has developed crystalline residue on one of the terminals. Thus the three stars on quality, and the comment about questionable durability. ymmv, but it's still hard to argue that it isn't excellent value for money.