I had a very similar (positive) experience going to the local store. I was able to walk in and buy my SGS4 w/ discount as well as my wife's iPhone and then stop over and eat lunch before going back to work. It actually took them longer to make my lunch order than it did to purchase the phones. I also received follow-up calls from T-Mobile asking if I had any questions about the phone, account, or my bill.
Prior to this I went through Best Buy because I had gift cards, coupons, a promotional offer, and they price matched Wirefly when I asked why the phone was so expensive at their location. I had an equally nice experience at both locations, but it did take a while longer at BB because they had to go through some absurd online and call in service to port our numbers over. It was much harder to leave sprint because they didn't want to let me go as a customer and offered me no incentive to stay. I had to make 4 calls and speak with their entire chain of command to simply speak with a knowledgeable accounts manager that could assist me with the termination.
It also seems to be another one of those YMMV experiences, where the level of caring can change from store to store.
Samsung Galaxy S4 – T-Mobile | Samsung Galaxy S2 Epic 4G Touch –
Sprint | HTC Hero – Sprint | Samsung Blackjack II – AT&T | Sony Ericsson W41s – AU (KDDI) | Motorola V265 – Verizon | Kyocera 2235 – Verizon