I had an Olympus D-560, which I beleive is similar to the stylus 300, but not water resistant. I hated it. I returned it, bought a Sony, returned that and ended up with a Canon A80.
Pros:
1. Compact clam shell design
2. Good outdoor pictures
3. AA type batteries. You can use rechargeable or regular alkaline in a pinch. The Stylus 300 uses a proprietary Rechargeable, which I don't like.
Cons:
1. Shot - shot time with flash way too long (7-9 sec). This is a stat that many reviewing web sites do not list. I found myself missing shots because of it. The Stylus 300 may have a better time due to it's proprietary battery.
2. XD picture card at the time was new and cost more money per Meg than other cards.
3. No manual controls. Being an amateur, I never thought I would move away from "Auto". Now I find certain conditions require some manual control.
4. Flash shots did not have a natural color tone.
5. The Stylus 300 uses a proprietary battery
6. No AF assist lamp, not sure if the Stylus has it.
I probably would have kept the Olympus, but it started malfunctioning a few months after purchase. My friend has the Stylus 400 and is happy with it. The price your getting for is good. I am really big on the AA type battery though. My mother-in-law's camera uses a proprietary battery and she forgot the battery in the charger at home for her daughter's bridal shower. It was too far from home to go back. She missed some special pictures. Had her camera been able to take AA's, she could have gone to the local store and picked some up.
Just my opinions.
Jay