I've had smartphones from the SP3 up and a couple of months ago took the leap to PPC ala HTC Prophet. Theres no denying the Prophet is a great device but I quickly (2 months) realised PPC form factor aint for me. Found txting an nightmare and the volume of the phone was poor enough too, made speaking around any noise very difficult.
I've never owned a flip phone so its all new to me but I find the S300s build quality very good. The hinge is solid and I feel like if I drop the phone its not going to smash into pieces, the rubbery texture at the front would help here. Its extremly light too, especially after coming from the Prophet I find myself checking my pocket to see if its still there (so far so good!)
The keys are very nice to use although you have to hold it right. For the 1st couple of days I found it very hard to hit the space (#) key but I've got the hang of it now, just hold the phone fairly low.
As I said volume was one of my reasons for moving from the prophet and I'm happy to say the S300s earpiece is excellent. I even have it at the 2nd loudest setting and can hear everything clearly.
Screen is on a par with the SP5, excellent if your coming from a non-QVGA screen!
The batery life was a bit of a worry seen as its a fairly low powered capacity 750mHa however as a test I ran the phone for over 2.5 days without needing a charge. I had bluetooth always on with some small usage. GPRS always connecetd again with some small usage and maybe 20 mins call and a played 5 or 10 min of video. Not alot of use but still 2.5 days aint too bad.
One annoying thing is the lack of storage space. Even with PIE files deleted (or moved to the storage card) and all media files and programs on the storage card I only have just over 5MB of space on the phones memory. As my Outlook a/c grows this may be a problem.
Well I'm crap at writing but theres some of my thoughts on it, feel free to as any questions about the phone.
PS- When we gonna get a Startrk section mods??