The
Late-2011 was the last decent MBP. I love Retina, but, I hate the whole "thin, thin, thin" thing with glued in batteries. Sad.
I had a 2009 MBP 17". After a couple of years, the battery was down to 70% and had started to swell considerably. At first I thought the trackpad had become wonky, but it was the battery that had become so big that the right hand side of the pad was no longer clickable. Opened it up and found that the MBP was powered by one deformed elephant man of a battery.
I had the battery replaced and it was fine for a few months before the graphics card fried itself somehow, rendering the whole thing useless (too old to be worth such extensive repairs). Resorted to iMac for a while.
2 years ago I bought a mid-2014 MBP 15". After 24 months, the battery is still at 97% health (it started at 106% so 97 isn't as impressive as it sounds, but still very good), and certainly hasn't swelled.
Point is, I don't care if the 2014 MBP battery is held in place by superglue, soldering, nails, staples, bolts, velcro, ultrasonic weld or llama spit – it has served me so much better than the 2009 MPB battery, which I miss like I miss the removable batteries of my late 90's Nokia and Ericsson phones, i.e. not at all.