These are only 13 points more per model than Strike Squad models and are twice as durable against small arms fire and infinitely more durable against AP3 or better weapons when not in cover. Plus they have 2 attacks rather than the 1 that Strike Squad guys have and of course they are Relentless so can move and fire the Psilencer and Psycannon to full effect and then assault. It is also worth remembering that Grey Knight terminators carry both frag and krak grenades unlike regular space marine termies and so can still strike at full initiative with their Nemesis weapons when charging through terrain. In fact I would say that their only downside when compared to a Strike Squad is the fact that they cost more and the special weapons also cost more (by 5 points each), but also they can't sweeping advance which is a fairly big deal sometimes, but in no way off sets all the positives.
In conclusion don’t bother with strikes, load up on termies (by that I mean fill your 1 minimum troop selection with a 5 man terminator squad!)
As Matt says, in 7th edition Troops aren't as relevant as they once were. In the Wolves book you'd probably want some of them anyway but here I think there are better units to spend the points on. Of course, this assumes you're using the GK-specific detachment so Objective Secured isn't an issue.
The next post will cover the Elites section of the book and I have a fair idea which unit will shine there!