Briefly, I was there the last week in January. I strolled in to MK at 11:30 am, went to the kiosk. Asked for a Fastpass for Jungle Cruise, Haunted Mansion and Peter Pan. I got one for 12:40 for JC, HM for 1:50 and Peter Pan for 2:50.
I took my time and wondered over toward JC. I stopped and looked at the castle, chatted with some people, went to the Tiki Room and got to JC about 5 minutes early. I went on immediately. There was about a 35 minute wait in Standby. I left there and rode Pirates, went to Peco's and had lunch. Walked over toward HM. There was a "dance party" thing going on with the Country Bears, so I watched that for a while, then went to HM. I didn't notice the standby time for that one, sorry! Then to Philharmagic, Small World and over to Peter Pan, walked on. The standby for that one was about 50 minutes.
The key thing is that I have never been able to get a FP for JC or Peter Pan in the past under the old system. I was very pleasantly surprised. Amongs other things I then rode the Peoplemover X2, CoP, Buzz Lightyear and Stitch. I was out of the park before 6 pm.
The next day Epcot, arrived at almost the same time, about 11:15 am. Got a fast pass for SSE, Living with the Land and Soarin. (Test Track was broken) don't remember the times exactly on that day, but, I saved about 10 minutes on SSE (no big deal), Living with the Land I didn't use because it was a walk on either way. Soarin was for around 4:30 walked on, with a 70 minute standby line watching. I also went on UoE, Mission: Space, The Seas with Nemo, and Imagination along with spending time exploring Innoventions. Oh, yea, had a nice lunch in the Land building too.
No glitches either at park entry or FP. Worked great for me and made touring the parks easier to plan with all three FP's in hand all at once. I don't know how it will work during the busy season, but, I was great for me.