Three Years later and this is about the only info I can find on this subject :(
We are just starting for the first time and this is the build I chose (currently at fifth level, so I haven't done any research on the higher level stuff yet). From everything I've read on all the concerns and other options available, even if you allow fabricating ammo this class is still not a game breaker and there are more powerful combos.
The main thing is that it allows versatility for a creative player. I think it is full meant to duplicate low level spells with tech because every tech option out there is significantly less powerful than the spells. You can't just summon a translator to translate a dead language, but I could use comprehend language to do so. You have to be at least 10th level to be even able to translate a living language unless you can download a language file (I would assume a fabricated translator only has languages the creator knows, but that is a GM call).
If the GM isn't on the ball and lets players get away with things more powerful than their level equivalents than, sure, it can be broken. But then that's a GM problem and not a balance problem. On the other hand, if the player is not creative it's a straight up waste. This build trades off various damage increasing abilities. Doing a focused build I won't be able to get something like Energized Spell until later (and you can only use it once a day). Trying to do it earlier is pointless because it makes the build less optimal by either giving up Fabricate Tech (making it pointless) or give up Fabricate Arms (which is better from a offensive perspective). The benefit is that I don't need to take some of those situational spells that may or may not end up being useful and have a limited version if I do need it or I can take some of those situational spells and burn them for weapons or other situational abilities as needed (I hate to take Comprehend Languages and Detect Tech instead of damage spells but or campaign will totally require their occasional use)
Ultimately it depends on the GM because certainly in battle heavy games Fabricate Tech is not as useful (It mostly is a very limited rental business), while in an RP heavy game it will be more useful but still limited. Meanwhile, Fabricate Arms will be of little use in a RP heavy game and more useful in a battle heavy game since it gives versatility in attacks and defense but still limited to a short battle. We do balanced games, so this is an obviously good choice for me but will certainly be better in the RP department than the battle department because there will be others that are stronger in that area.
Unfortunately, because it was poorly worded in the first place and has received little love that I can find to fix the flaws, it is a huge headache to figure out the can and cannots with my GM. That is why we are making a pre-game list of useful items (which solves many of the complaints about mechanics during game... my god there is so much tech in the Armory that this is a huge headache for those like me with decision paralysis and slow reading).
So, to the people here that have been playing around with Fabricate Tech for a while, what are your thoughts now on what's useful?