I've only just seen this thread. Both my sons had a tongue tie so I have every sympathy. Both had it divided (eventually) and I can honestly say it made all the difference.
First time around, breastfeeding was agony. Worse than contractions. DS1 wanted to feed every 25 minutes and each time I curled my toes and cried. I bought book upon book on b/f technique and had numerous sessions with the midwives who couldn't see what I was doing wrong. After weeks of showing my (infected) cracked nipples to anyone willing to look (I am usually very shy), I finally went to the doctor who made me stop feeding for a week to protect DS1 from the infection in the cracks.
When I started again, it was no better and I was worried about the bond with DS because I just couldn't stand him anywhere near me. I was in too much pain. I finally insisted on seeing a breastfeeding counsellor who diagnosed it over the phone and referred me to the wonderful Mr Griffiths in Southampton. DS1 was taken away for 30 seconds, came back a little red in the face but not crying and fed straight away. No GA, no stitches, nothing.
Within 2 days feeding was painless, down to every 3-4 hours and a lovely bonding experience. DS was much happier. Looking back, he was simply starving and exhausted from trying to feed when he could not latch on.
Second time around, I saw DS2's tongue tie in the delivery room and insisted on being referred before we left. The paediatrician at the hospital divided it at nearly 4 weeks old. This time I went into theatre with him. It is such a simple procedure: they lift the tongue up and snip beneath. There was a tiny drop of blood but once he had fed, it was gone. Again the difference was dramatic. I also noticed he was a lot less "windy". I imagine in his efforts to hold on for dear life, without making a proper closed latch, he was swallowing lots of air.
From my experience, I am ardently in favour of division if it is causing feeding problems. I have large scars from the infected cracks and I am quite annoyed that it took so long to pick it up. I saw 5 midwives, a health visitor and a GP before someone realised what was causing the problems. Most had also looked in DS's mouth. It was obvious to me (the tongue was heart-shaped and curled up at the sides when he cried) that the tongue didn't look like a "normal" tongue, but as he was my first baby, I though perhaps they just grew. I'd never heard of a tongue-tie before and the professionals didn't bat an eyelid.
Let me know if you need any more details. I'm really pleased I went through the operation both times.