I've used it enough to get a feel of it. For me it wasn't so much the performance, it is the horrible look.
I'm going to try a different approach; if you're so hooked by 6, then jailbreak your ipad to save the blobs, then update to 7.1. Coming from a regular ipad 2(!) user, 7.1 is a world of difference. Of course the UI is drastically different, but I love it, even though I hated it at first. It grows on you. And I have a non-retina screen. The thin typefaces are are really nice, and the overall coherency is great. Of course it takes some getting used to, but it's worth it. Apps finally now have a similar feel! It also has many more features and supports new, cool technologies. Your ipad is more than well-equipped. Again, my iPad 2 runs it like a champ; after ios 7.1, it's as fast as 6.
Trust me; you can always go back in 10 minutes if you save the blobs, so what do you have to lose? You just restore your ios 6 backup when you go back.
Office is ios 7-only because the UI was specifically created to match the clean flatness of 7. They wouldn't make a whole new UI for an OS that's on a vast minority of devices. That's why.