I bought a Garmin 196 a couple of years ago. It's a fantastic piece of kit and, given that Garmin are now focusing on much more expensive colour GPSs with terrain, etc., the price of 196s is coming down and down - looks like around £500 now. The mono screen is easy to read and clear even in very bright sunlight.
I'd strongly recommend that you use it. It really is a sophisticated navigational aid. The screen is significantly bigger than the smaller Garmins.
Not wishing to start up discussions which have taken place already on the site, but... I have always used pdas - since they first came out - in business and personal life. I have had many - at least two HPs and four xda's of various types - but I would NEVER use one in an aircraft. Why?
1) Their screens are not powerful enough in the (at times) harshly lit environment of an aircraft cockpit.
2) Their battery life is uncertain.
3) They are simply NOT reliable enough. Connectors, components and switches are all tiny and delicate and they pack in now and again and ofter without warning. For example, my current xda Exec, which is nine months old, has an intermittent fault and will periodically freeze and need to be reset. The software also, even WM 5, is typically Microsoft and will periodically need to be reset or will freeze itself, etc. Think Windows 98.
Whether you like it or not, legally a GPS is a backup to your primary navigation. A quality GPS is a secure and stable backup which is unlikely to let you down unless the signal is played with or you lose power and which, in conjunction with prudent VFR or IMC navigation, will enhance your safety. The pda is NOT designed robustly and may develop intermittent faults. It may become a dangerous distraction to you at a time when you should be focusing on your primary (VFR or IMC) navigation. And if it's not reliable then it can hardly be an effective backup either.
Pocket FMS is a really great piece of software and they seem to be terrific people, but I'd be scared to use it in the air.
I use the Garmion 196 in conjunction with my xda Exec. I plan my route on the map, then enter the waypoints into the Garmin 196 to use it as a way to calculate the legs of the route. Then I enter these waypoints into 'fly.com' on the xda Exec, using G3 or GPRS to access the internet. Then transfer the resulting numbers onto a paper plog. That gives you a proper route plotted on the map, an accurate plog with less scope for mathematical errors and an automatic backup of the route on the Garmin.