Group Policy is very much overkill for Small Business Server. So much in fact that many of the features won't even work on an SBS box because the relate to cross forest or cross doamin functionality. Having said that. Group Policy can still be cumbersome to troubleshoot within a single Domain and Site. What you need is troubleshooting tools.
There are a few primary tools I would want to call out around troubleshooting.
This handy Windows XP tool can be run by simply typing "rsop.msc" from a client run box. It will gather all the details of policy running on that particular box and show it to you in a single GPEdit.msc console. It's not the easiest way to look at it, but if you're checking for a specific policy and whether it was applied or not, this is pretty easy. You even get funky red-x's if something failed to apply.
This handy DOS command can be run to roll-up and show you all the policies in your network and which ones are applied to the computer, and which one's aren't. Kind of handy if you were expecting a policy to affect a machine and it didn't.
GPMC "Policy Results" Calculations
If the user has ever logged into the client machine, you can go crack open GMPC (our handy Group Policy tool) and run a new query, it will take your computer/user combination and give you a nice roll-up of what's going on with that particular user. This is handy since it's an all-in-one familiar interface to view all the policies and how they are applied.
Happy Problem Solving!