I have done Memories by Betsy gift baskets, Disney Florist in room celebrations and gift baskets and I did have a custom event done by Gifts of a Lifetime (not room decorating).
GoaL does custom work so I would expect to pay more. Disney Florist does a great job and although they will work with you to switch a few things out, you aren't going to get a custom package--they are limited to using the items that they have been authorized to use.
Memories by Betsy is nice enough but it's not at the level of either Disney Florist or Gifts of a Lifetime. However, prices are much less.