Now that Alliance has been out long enough to fully acquaint myself with the new tools, I've become very fond of the Failsafe Kit.
I most often utilize Failsafe as a replacement for the Spanner (so typically that means Mallet, Failsafe, Ext/Chem), which I find does not affect my play-style very much at all. As head engineer, it allows me to act both preemptively and reactively. Preemptive in that I can slap a gweebo on most everything before combat, or reactively to repair low-pressure damage (>50% HP). It has also been HUGE for when the pilot needs to abuse the engines, because I can prep them beforehand and continue onto other things.
Since I already have Chem cycles and Spanner strats in my head, adjusting to the Failsafe was an absolute no-brainer.
The largest risk that Failsafe poses is a gradual health recovery over an instant one, and that it has less rebuild power than Spanner. Both are easily addressed by playing preemptively, Mallet, utilizing the rebuild special, and collaborating with the rest of the crew. I've never had regrets bringing it over the Spanner for ANY match, that's for sure.
What do you think? Praise and gripes? Success stories? FAILURE stories?
As well... I think about the possibility of incorporating the Failsafe into PVP a lot these days. With some adjustment, it certainly appears to be a viable addition.