Similarly to Chase & Status, who made pretty traditional drum & bass on their first album and then went on to make a much more commercial type of drum & bass (with lots of collaborations with other artists, some of them capable of making drum & bass, others not so much) and Qemists have done basically exactly the same. The difference between the two groups of that Qemists have basically attracted that don't work at all with their style, and also that few of the ten tracks contained on "Spirit In The System" are any good.
Take the first track for instance. Qemists? Great. Enter Shikari? Pretty good. Putting them together? Doesn't seem to work. Take It Back, as the track is called, starts of promisingly but simply ends up repetitive and boring. Hurt Less, featuring Jenna G, is quite a bit better, but it still falls very much short of the great tracks on the first half of the Qemists' previous album. Renegade is pretty good as well, with a catchy and powerful riff, and it is, in my opinion, the best track on the record. The others are very disappointing. If you want to buy a Qemists album, buy "Join the Q", not "Spirit In the System". The discrepancy in terms of quality is painfully obvious.