Actually, both didn't worked very well for me!
Chamberlain was promising but he didn't evolved much. Also, his low teamwork coupled with his very weak long shoting made him waste a lot. I also got James Rodriguez for a cheap 6M€ and Walcott was working bonkers for me in the MAD position so I ended up selling him.
Ramsey was pretty good the first two seasons but he didn't fit my tactic plan afterwards (it was working much better with either Wilshere or both MC's in a more defensive role, Alex Song and Arturo Vidal in this case).
Sold both for 36M€ total.