I ran the 1st 2 adventures from the magazines. I thought I only had 2 players, so I let them play 2 PCs each. I added Star Wars human jedi consulars & guardians; Judge Dredd Street & Psi judges; Omega World mutant human explorers; & aasimar paladins w/o the +1 ECL as PC options. Most times I actually had 3-4 players, but 6-8 PCs were still overmatched by some of the encounters. At times, only a couple survived because they had lightsabers or guns. It took 7 months, so the pace was a little too slow. And, the game gets a little too complex by these levels (around 5th), although that's a flaw with d20 D&D that is probably peculiar to me & my group.
I've dropped the jedi & judges. If I continue it, I will still allow mutants--I really wish I had just run it as an Omega World game from the get go to avoid the magic arms race. Other options I've considered are limiting magic (insanity or no external effects) & eliminating hit points (in favor of a damage save-type system). But, I'm not sure what would "fix" the game, if anything.
So, it's a great series--just a tough set of adventures in an increasingly complex game system. I have really considered getting the hardcover in order to continue it more coherently. I think you would enjoy it. Heck, we had the better part of year's great gaming with 1/6 of what you'll get in the book.