Both the Cochin University of Science And Technology (CUSAT) and Federal Institute of Science And Technology (FISAT) are very good institutes and have almost similar rankings in the state of Kerala. Now you can compare both the institutes on various parameters. I have taken two broad and the most popular parameters for this comparison.

Placement - In this regard, the School of Engineering (SoE) of CUSAT is better than FISAT. According to the recent placement statistics, the average and highest CTC offered at CUSAT is 4 LPA and 15 LPA respectively. Cochin University College of Engineering Kuttanad (CUCEK) campus of CUSAT is also similar to SoE in terms of placements.

Infrastructure - Here FISAT takes an upper hand and has better facilities than both SoE and CUCEK. SoE is slightly good and is comparable to FISAT but CUCEK lacks a lot of facilities compared to both.

So it totally depends on you and what your priorities are. If you only aim for placements then choose CUSAT. If you want good infrastructure, then FISAT is preferable.