That's a great bonus up from FTTC 76/18 to FTTP 100/18 - better than nothing!
Its a bit tight though, I had 100/30 on Digital Region over VDSL. The only reason OR was limited to 76/18 was a technical one to minimise crosstalk.
Still it could be worse, with Virgin doing 50/5 for £38, 108/10 for £44, 213/20 for £50, 362/36 for £56, 1130/52 for £60, its downright insane pricing there.
IMO FTTP should have a base package of 100/20 across all ISPs, its good enough for most people I'd expect and you can't get the price low enough for slower to be worth it.