Lets me relocate AND shoot the big guns, since otherwise the enemy can try to gyp me out of a turn of shooting. I'm unfamiliar with the Forge World suits other than how they prefer the ASS on the Broadsides. Septemat 10:32 missed that bit, but it explains it more succinctly than I did. Otherwise, great basic write-up on the Crisis Suits. Of course, in our current codex, this doesn't matter at all when you start using Forgeworld variants, however, it does come into play. Since the codex stipulation states that 'they must remain stationary' and Relentless says they 'count as stationary,' we're all set here. Just for clarification, Crisis Suits can move and fire Heavy Weaponry, as their Jetpack grant them Relentless.
Missile pods are a must, they're just too good, and when facing a lot of marine armies, those Plasma Rifles are wonderful especially since they don't 'get hot'! It actually makes a sort of sense, since it gives them a weapon they can move and shoot without ASS.
Markerlight a target and this unit turns into a kill-switch. I like to take a unit of three and attach a couple of Shas'els with 6 shield drones for durability. A solid review of the options, and I entirely agree with the Fireknife being the default workhorse of any Tau army.