I had the battery and the 64 Mb upgrade done at PPC Techs.
The results were both very good!!! I have enough room for a lot of applications and memory for surfing too - plus I charge my battery about once every two days now.
With my old Toshiba's - I was charging them every night as they would loose 1/2 their charge in one day; one day of heavy use with my XDA-I with the larger battery from PPC Techs I use only 30% !!! and have 70% left - yes it is that good. BTW, 1 day of heavy use for me is ~12 hrs of use with 2-3 hours surfing and 20-40 min of calls, 2-3 hours PDA PIM stuff & the balance is idle time.
So, IMHO, the upgrade IS worth it...
Current/Active: Galaxy Note 3 / Nexus 7 / EeePad Transformer
Reserve Duty: Galaxy Note 2 / Galaxy Nexus
Yeah, I'm an old PDA/Phone hacker/user . . .
Check out my Android Apps: http://goo.gl/2LPbx