Ac syndicate is one of the best games in the franchise.I really enjoyed it.
I liked both Jacob and Evie although gameplay is very similar between them.
I didn't like unity,it was a glitchy uninspired piece of shit but syndicate really nailed it.

I enjoyed Unity, but then again I paid £15 for it brand new and played it 6-9 months after its release.

I loved AC2, but then they started to churn out the games annually and by the time 3 hit, I couldn't be bothered anymore. I realised then it's best to wait 6-9 months before buying an AC game as they will likely launch it rushed to meet its 12month deadline. You pick it up later, you get the patched version with far less problems or non at almost 1/4 the cost.

I finished it recently, its one of my favorite Assassin's Creeds, altough I still didn't like the "modern world" parts they where minimal and overall the twins where just great and it was one big playground in one of the most beautifull settings/locations ever in a videogame, great stuff.