I've just ran a test of my Jetboil PCS to see how it compared to my other mini stove, a Mini Stove C-3 bought off ebay for around £12. I used the same stove in my EtaPower/Gelert test. The procedure was the same as before, 500ml of cold tap water, a new 100g cartridge and I used the same timer and thermometer. I consider 98deg to be boiling as it's virtually impossible to hit 100deg (water actually boils at 99.6deg IIRC. I weighed the cartridge before and after although I didn't video the after boil weight, in any case it was 183g.
I used the same cartridge to test the C-3/Mitymug which if there was any performance drop should have placed the C-3 at a disadvantage, I doubt there was any significant difference.
The Jetboil test is below, I'll add the C-3 Mitymug as soon as it uploads.