I have a mild dilemma

Yesterday I bought a copy of Microsoft office home, since in my line of work EVERYONE uses office documents as the standard format.

I doesn't have all the functionality of the full version, but it was about £90 instead of £350.

On the back of the box it says 'licensed for noncommercial use on up to 3 personal computers'.

I KNOW I shall use the computer to work (and hopefully to make money).

I've not previously bought office for home use.

My dilemma is: can I use the software in good conscience, knowing that I've paid M$ money for something with reduced functionality compared to the full version, or is that compromised by using it for any kind of work?

I've looked at Open Office, and found it to be usable, but not as good as the M$ product. I have looked at another suit for which there is a charge, and while it *looks* nicer and would integrate with the computer well, it appears to be functionally blown out of the water by Open Office in terms of handling Microsoft generated documents.

What to do?