Thumper wasn't...but he wasn't neutered when I brought him home either. I had to take him back for that and boy was he a handful. He still is, but not like before. I did see results immediately after the neuter. He didn't pee/spray as much, though he still did.
He got much better when Peaches came home. I have just resigned myself to the fact that their are times that he will spray so he is not allowed on my couch any more.
Peaches came to me spayed and litterbox trained. She is GREAT. No stray poops and she has never pee'd on anything other than her litterbox. She did, however, throw her litterbox around and made such a mess. So I got her a corner box with a grate on top and never had a problem since.
So, to make this already long story short, it really depends on the bun. I'm sure Cindy will have a number of buns that are already litterbox trained and if not, it takes a little time and patience but it will be worth it in the end.
edited to add: oops, forgot to mention, it took T about 5-6 weeks to be litterbox trained. I must confess, he is not yet perfect and has been with me for over 3 months now.