iPhone 3G 3.0.1 Pwn'd to 3.12 (or 3.1.3)

I'm still on 3.0.1, 4.26.08 (3G), unlocked, T-Mobile USA, pwn'd w/Pwnage. Never updated to 3.1.2 due to several issues that surfaced last year. IE: carrier logos not showing, tethering issues, maybe more. I know some are fixed, but trying to be careful.

Is it time for me to upgrade (w/Pwnage 3.1.5?)? ... some apps require 3.1.2.

... BUT... do I or could I loose anything by going from 3.0.1 to 3.1.2 (or 3.1.3)? :spinme
(I fully understand about reinstalling Cydia apps, etc, etc ... that is a given. I'm asking about possible crippled functionality)

BTW: Waiting for 4.0 is not a option. I take FW updates seriously, and always wait a long time until all the dust is settled. Seems like I'm always 2 or 3 versions behind most others :):)

Go to a cust 3.1.2, it is stable now.

Only go to cust 3.1.3 if you have a 3GS and your battery status is seriously playing up.

Thanks Olethros for your advice. O:)

I love to customize this Darwin/Unix beast :) -- not with Winterboard themes, but manually. Winterboard is used for background pict only. For example, I'm still changing the Preferences/General.plist file to add screen Dim, my custom T-Mobile logo, my SMS sounds, etc. Finally tried push --- and love it. With Apples recent success (ie: tethered 3GS (iBoot), 5.11 baseband unlock issues, etc), I have been more cautious. Good to know 3.1.2 is stable and a good place to settle until maybe 4.01, 4.0.2, 4.1 (haha) issues are flushed out :)

Updated: I just remember another reason I stayed with 3.0.1. 3.0.1 allows long (appx 30 sec) sms received sounds, same as 2.2.1 .... and if I'm not mistaken, 3.1 changed the length to something like 10 (or less). Am I correct?

Update:
I successfully updated to 3.1.2 w/PwnageTool - using ultrasn0w for T-Mobile.
Thanks to PKGBackup, my Cydia apps were reinstalled correctly.
Somehow I lost the 'user data' for AppStore apps, but was easily recovered.
Everything is working and noticeably faster.