Since we're having a Flight Following availability thread, I'll share my experience from my first true cross-country last week (DC to LA). I flew from KGAI in Maryland over to Kansas City, down to Albuquerque, south to Deming NM, up to Phoenix, and over to LA. I had flight following the entire time, even when I was picking my way around the mountains at just 6500' MSL between Deming and Phoenix (ceilings were too low for higher, but air was smooth and vis was great). Even when I started dropping off radar on that segment the controller kept me and would periodically ask for my position -- I like talking to someone, especially over the middle of nowhere, so this was very comforting for someone far from home.
I was expecting, based on stories I've heard, that I would have trouble getting FF or they would frequently be dropping me, but I never lost comms with ARTCC or TRACONs the whole way, and when I did drop off radar they kept me on the code and kept talking to me until their radars picked me back up. I was impressed with the level of service I received out west compared to what I get back east where it's more common to get a busy controller who doesn't have time to deal with you.