I never got into BF3 as I went off and played Skyrim half to death and got left behind. Had a really good night playing BF4 last night though and particularly the new China Rising maps.
BF4 is a lot more like BF2 in how it's played. Squad size is up to 5, voice comms and commander is back and it just feels a lot better.
There's a lot of really good innovation with the series but it's gotten a bit complex in places with all the weapons attachments and battlepacks and awards etc. Some great touches though. I have a Daffy Duck emblem that I had to design myself and it gets layered on to all the vehicles you drive and even on your weapons. It's pretty cool (a bit like the sprays in CS:S).
Though using an internet browser to launch the game through Battlelog is a good idea (kind of like the old All Seeing Eye days), it doesn't properly at all and neither did it in BF3. You're meant to be able to click on the 'Players' column to get it to show you rankings by populated servers but it's shot to blazes. It just doesn't work so can be extremely frustrating trying to find a suitable server to play on. I really need to look into other options there. I don't suppose Xfire can be used either...
BF1942! Glory days! I've still got the game installed on my PC and there are still people playing it I bet. Crazy bu.ggers.
I certainly would recommend BF4 but only for next gen or PC really.