This is my second WinMo device...when I had my Mogul...I ran stock ROM and radio...and I dealt with the battery life and the lack of memory (no multitasking.)
Since I bought my TP...took me about a month to take the plunge into flashing a custom ROM...(Y4J's Clean) I thought I'd died and gone to heaven. No more bloat-ware, no more battery lasting half a day, and the phone was SOOOO MUCH FASTER. Flashing a new radio came later...and I was really skeptical...until my battery lasted me a day and a half (moderate use.)
Bottom line...flash...flash and you won't be sorry...
unlock your phone
here
read up on flashing
here
on the different radios
here