If you have a city mini gt stroller, which infant car seat do you use with it (and the adaptor)?

We are thinking of buying this stroller and have a Graco Snugride 35 (from my brother, which is one year old, in good shape and still meets all the safety regulations). However, we had a strange experience in the store with one sales person telling us the seat fits perfectly with this stroller and then another telling us it was a bad idea to use Graco with this stroller!?! (this was after she couldn't figure out how to fit the adaptor on the stroller properly and fit the seat in) Has anyone used a Graco seat with this stroller?