Yes, piece-by-piece is the movement :). I've had experiences with Reloop, and I don't like the brand nor their products. So I wouldn't recommend Reloop products! And the fact that the Kontrol X1 comes with a free version of TP2 is a deal breaker (at least, it was for me - got it with the bag for € 199,-). Or you could maybe wait for the new Traktor Controller which has been teased today.
But it's up to you. I can believe that one would like the Reloop Contour!
Well, spot on! For me, the TP2 FX are a compliment to the DB2/4 FX. I've played with the DB4 (and reserved it afterwards, hehe) and damn, the Delay is just amazing. Incredibly versatile and they sound so damn professional! The FX from the DB2/4 are coming from the iLive-series, they're like the best mixers out there (not for DJ'ing, but for festivals, churches, etc.) and have studio-like FX. So the DB2/4 come with studio FX and compared to the FX from Traktor and other mixers out there, they're beating them with ease in terms of quality.
Though I don't like the Reverb of the DB2/4. I'm going to use the Reverb of TP2 and maybe in the future, buy external hardware (like the EvenTide Space). So in my case, the FX from Traktor are complementing the FX from the DB2/4!