When it comes to Older Macs, I will say (Like others have said) to always do your research on the machine before you buy it-- That way you don't wind up in a situation like you are in now.
There's nothing wrong with G4s, or any older computer, just as long as you know it's limits... I use my 1.25 G4 MDD (2003) for Video, Graphic and Audio editing, but it is a more powerful machine than the 400mhz G4 you have...
As long as you are aware of the machine's limits (no ipad compatibility, 10.4.11 the last OS supported, etc.) you should be fine.
I
personally wouldn't Get rid of the G4, you might be able to put it to some good use... Maybe as a server?
1 security and compatability with my iPad and iPhone
2 photo editing and work related
3 ease of use
4 speed
5 fun
You have 2*,3,and 5 going for you; and 4 if you install the right OS.
(*If you install the correct software that is compatible)
Of course I'm Not quite sure what Use it
will be to you; Don't expect it to function or be compatible with the latest and greatest. Even G5s are starting to become obsolete
[Obsolete Tends to be seen as a derogitory term; Though I Don't use it in that sense. An "Obsolete" Machine can still Be very helpful! I use a powermac 6100 running OS9 For internet Radio... Sure the machine is "Obsolete", but it does what I need it to do...]
If you DO want compatibility with the latest things; Intel is the only way to go.
Again, Remember the machine's Limits.
Just a word of advice. err... many words of advice... (you know what I mean)