This is my main work app.
For excel compatibility it's fabulous. Never had any issues. My excel files aren't that too complicated saying that. But even so, they work lovely. Cells, colours, calculations, tabbed pages etc etc, the whole visual and experience works great. I typically do my business time sheets and home accounts on it.
Gripe - when typing values into cells it only displays them when you've finished and hit 'done'. No live text typing. Not really a big issue, but it's always nice to see what you're typing as your typing it
Word docs are a different matter. Even for basic letter setting out I've found the compatibilities between Office2HD and other word apps, ie, ms word, not very interchangeable and compatible. Whatever file format I've tried out the page layouts and tabbing just doesn't carry across platform as you'd like.
Saying that, you can certainly set up, and very easily set up, your letters and templates for docs in the applicatin exactly to your liking, and they work and print lovely. But as I say, transferring back to Windows MS or whatever can prove iffy. My advise would be to stay in the app. Excel is a lot more forgiving in this situation.
My tips and main conclusion - I find Office2HD is a great app. Works well and is fairly adaptable and compatible with ms office on the whole (excel more than word). You'll get much more out of the app if you stay in the app.
Also, and because of the above point, you might find your doc page formatting and excel page set-ups don't translate over exactly true between the softwares to how you'd ideally like, so I suggest to stay in the one app as much as you can and re-format and re set out your page formats as best you can in the app from the start; then stay there. Save yourself a set of template pages and life becomes easier.
This will suit the app perfectly and you can get a perfect looking page.
Saving and backing up and wifi transfer is a breeze too.
There is no definitive iPad office app as yet, especially one you can easily and painlessly go back and forth between iPad and main computer. and all have their pros and cons.