The server I play on went from Ult to Unleashed - honestly without GregTech i'm now bored. I was going to make a stupid large Solar array, but Uranium is my limiting factor. There was a complaint on another wiki about not having a UU recipe for Uranium and was replied to about it being removed due to being game breaking. This is one of dozens of complaints i've seen being accounted to "balance"
I'm sorry, but how is the cluster of mods in these packs not self-breaking to begin with? Why would i use 9 UU to make a diamond when 5 will make 2 gold ore which i can EE3 into a diamond? Mystcraft automatically breaks any resource issues including solar panels - which is what my Mass Fab runs on, 2 Ultimate Hybrids in a world without night (making about 1 UU every 2 minutes, without scrap). I originally prep'd the mass fab with 2 steam boilers infinitely fed by Oil Fabs until i had the iridium to make the panels.
Recipe costs aside - The Mass Fab functions without being fed. The Matter Fab at least shuts down without scrap
EE3 combined with any of the machine mods - broken as hell
Mystcraft + Quarries (no night, even a crap solar panel) - Who needs to worry about resources? Given some of the CC turtle programs i've seen lately, who needs a quarry?
Power Convert is nice, but should have a cost. The savings of SPACE is more than enough reason to build them let alone the fact you lose -zero- energy in the conversion. Combined with lava power sources that never seem to run out of output (a single pump is running 20+ magmatics currently plus friends).
Strangely, in Ultimate AE storage was harder to make because quartz was a lot more rare - now i'm drowning in it in Unleashed and sitting on 32 and 64k cells simply because i had the materials.
I've never seen these packs as a "New level of gameplay" they're just mods that are fun together and let you do what most people want to - Build ridiculous things without creator mode and less concern about the mundane aspects of mining and farming. None of these mods were exactly intended to be used together, but without each other they're not deep enough to stand alone (EE3 for example).
I'm all for gregtech, as annoying as it is to begin with once you get going it's not so bad and gives you something to work for. People just seem to complain about balance issues and 'difficulty' without addressing the underlying issues of compatibility