A web-service is a great way to go; there really is no reason to be using desktop software for business management any more unless you don't have reliable access to the internet. With a web-service you don't have to worry about installing or upgrading software, compatibility, backing up your data, or your computer crashing.
My company also offers a great web service solution specifically geared towards the on-site service industries. It's brand new and has the benefit of being based on newer, more robust technology than most of our competition. Our focus was on developing a product that's powerful but still very easy to set up and use. Also, you'll find that our pricing is much more reasonable than the other options out there.
Check it out at http://www.octopusapp.com
. There are no contracts or commitments, and we have a 30 day free trial. Use the discount code 496LAWNSITE15
when you sign up to get 15% off your first three months after the free trial.
Let me know if you have any questions about the software, or even just web based software in general.