Erin Radfordwrote a review of MSR TrailShot Microfilter on January 9, 2019
In the winter of 2017, I bought my MSR Trailshot, took it to the river to try it, and made a video that you'll find at the bottom of this page. I was pleased with the performance, it was certainly much slower than my old Pur (Katadyn) Hiker but the weight savings made up for it. I cleaned and dried it per MSR's instructions and it went into a drawer.
Fast forward to summer 2018 - I took the MSR Trailshot to the Beehive Lakes in the Selkirks and was bitterly disappointed in the performance. I pumped like a demon and only a pathetic trickle came out. Ugh. I managed half a liter and gave up, I borrowed my friend's Sawyer Mini for the rest of the excursion.
There's no way the Trailshot froze, it was stored indoors prior to the great disappointment. I've since read that hollow fiber filters can become fouled by hard water. Well, I have delicious but hard tap water at home so I suspect that I killed the Trailshot myself. In the future, I'll purchase water to clean my hollow fiber products.
Now, this failure was my fault but I have to say, I'm not at all interested in getting a new MSR Trailshot. I didn't enjoy using my friend's Sawyer Mini but my primary objection was filing the Sawyer bag from standing water. With the releasce of CNOC's Vecto bags, that's no longer a worry. Also, Sawyer has released the Micro Squeeze which improves upon the Sawyer Mini's flow rate and has threads on both ends - you can use the included blue coupler to backflush with a clean water bottle/bladder & leave the silly syringe at home.
The main reason I wanted the MSR Trailshot over the Sawyer was the cumbersome water collection method. Now that it's been resolved by the CNOC Vecto bag, I just can't see a place for the Trailshot.