The wifi is excellent, the PIMs are pretty much useless by comparison with Palm, Mac or Windows unless you are ALWAYS connected and use the Google stuff.
Nokia support hardly exists. There's a person on here who is delighted with Nokia because they dealt with his faulty machine after 2 years!
I'd say the N810 is an entertainment machine at root. I love mine but I really need a Palm AND the Nokia.
There is very little choice of software for the Nokia by comparison with other platforms. What there is is mostly free but I'd prefer to pay and have a choice.
To sum up, for fun, YES. For business purposes, NO.