I think the limit is about 20 cheques and about 50 electronic payments in a month. The fees are about 35p per item. I rarely get a bill of more than £5 purely because we tend to have larger clients who we bill large amounts. A typical invoice for us is £10-15k. My coaching clients pay for several sessions in one go so I don't have bitty cheques or cash to pay in.
They do change their deals periodically so it's worth popping in to see what they're offering now. They do call you in for a review periodically and, apart from trying to sell me their hideously overpriced professional indemnity insurance, they usually look to see if I can avoid any charges.
I don't think any banks are saints but I haven't had a problem. Lloyds TSB froze my personal account once when I paid a large dividend in (apparently for security reasons - although my company has my (not that common) surname in it) but that's a whole different story!!