Hi all, first post but have done a fair bit of reading

Normally I make my curries from scratch rather than make a base, however yesterday I made a load of DarthPhall's base and (slightly modified) madras and it was very very good. So I am a convert to first making loads of base and then making whatever curry around it. I also like the addition of carrots and celery which I don't normally do.
Anyway, I already make a damn good curry ; that's pretty close to a BIR, but I start by chopping onions super finely (so no need to blend) and then gently frying them for 45 minutes with garlic/ginger until caramelised, then adding spices, meat etc etc. I also thought the key to an authentic curry was the way you fried the onions, so I was quite surprised to see that in most of the bases you basically just boil them for an hour or so.
So what's the pros and cons of frying vs boiling do you think? Do yu get the same rich sweetness do you think?