Hello,
congrats for your decision!
I'd suggest to install at least two additionally packages, namely the Filer48 from Raul Del Cid Lopez, and the SpeedBrowser (from me;-)
This way you have the best file manager (Filer48) around, and the fastest configurable browser for the built-in equation library and more (SpeedBrowser). With SpeedBrowser, you can easily create your own browser windows.
Filer48 looks and feels similar to the filer in the 49g/g+ .
In general, number entry will be faster on the HP-48, because of the reliable keyboard action, you can even type relatively fast, the HP-48 has a key buffer. You can even type without looking at the calc (once you know the kbd layout), since you can be sure that what you type is what you get (on the HP-48 only).
The input forms on the 49g are faster due to many code optimizations, but the ROM upgradeability isn't a real plus for the 49g against the HP-48, because the OS of the HP-48 is simply stable,
and the very few flaws are well documented, and don't affect the user in most cases.
Raymond