Of the four Mission Kits currently available, the Stealth Ops kit was the most interesting to me.
Let's take a look at the "Proximity barrel" first.
Next up is the Red Dot Sight.
Finally, the Folding Grip.
Note also that the Folding Grip has a weird hook like structure at the bottom, not sure what it's about.
Here's the Stealth Ops kit on some blasters.
Being that none of the attachments significantly improve the blaster they're attached to, the Stealth Ops kit is entirely for tacticool. If you're a purely practical Nerfer and/or on a tight budget then obviously give it a miss. If you're looking to jazz up a blaster, then naturally the SO kit is a solid candidate, provided said blaster will accept the attachments obviously. It's all personal preference really, if you like red dot sights, folding grips and/or stubby barrel extensions (or completionism for that matter) then the kit is worth a look, but it's certainly not an essential purchase. I think it's best suited to the Stryfe, but since there's little practical use to the parts, it's all about personal preference.