Fester, I'm no boffin and the work I do in Word or Excel is pretty simple stuff, but I was, like you, concerned but having had the machine since the weekend and done a small amount of work in both formats in Apple, I can assure you that Apple software converts it to it's own format with ease and without any loss of data or formatting. Apple software is simpler and far more intuitive than Microsoft, although I've not delved into the difficult stuff (formulas etc) that an accountant or publisher might use, but so far, it's superb. I've sent AppleMac 'Excel' files (Apple call it 'Numbers') to people without them even knowing that I'm in Apple. You can transfer data in numerous ways, but a cable link appears to be the easiest, or get the supplier (PC World) to do it for you.
PC World were actually very good and most helpful, I was quite impressed with them. I prefer to deal with people over a purchase like this, rather than an internet purchase, because unlike the internet, you can go back and poke them in the chest in the event of it going wrong. The manager at Currys PC World was very good and I'd recommend that you speak to him direct as a couple of his 'salesmen' are not cut out for retail.
As for transfer, I've had no problem whatsoever with data transfer, no loss of data or loss of format. And the photography filing software is stunning.
To me, the whole operating system is light years ahead of Microsoft, others may disagree, but that's what we feel. If there was one small thing that was wary of at first, but I'm now used to, and that is the keyboard is quite small, especially for someone as hamfisted as me, but now, after three days I actually prefer it as it's faster to use, as your hands and fingers don't have to move so far! It's not like playing a church organ keyboard like a PC.
In all, I'm a very happy convert. Don't hesitate to contact me for anything further I can help with, but remember, I am an Apple beginner!