Quite a few of my friends in the Texas Bushcrafters community swear by the Grayl Geopress but I personally find them too pricey. The main reasons they give for liking them is they can purify a decent amount of water more quickly than other filter systems. They also prefer them to boiling water because most of the time no one here in Texas wants to drink hot water or spend hours waiting for the water to cool.
-Blast

I have a Grayl (and almost every other filter imaginable). I like the Grayl for international travel. One looks like a tool pulling out their Sawyer or whatever in a restaurant in India. But no one notices when you pour your water into your "water bottle" and drink.

For outdoor use? Not so great.

Thanks for the feedback, much appreciated!

I had been looking at the Katadyn BeFree Tactical filter and collapsible bottle.

https://www.katadyn.com/en/de/50541-8020426-BeFree-1.0L-tactical

Luckily downloaded and opened the PDF manual.

"The Katadyn BeFree™ does not remove viruses."

That's a terrible omission on their product page.

"This filter removes bacteria, cysts and sediment with its pore size of 0.1 micron (0.0001 mm)."

Good catch Ren.

It's a filter, not a purifier. Know the difference.

Plenty of hollow fiber (and pretty much all ceramic and glass fiber filters without additional treatments) are filters.

[b][/b]In backcountry US, viruses are not generally considered an issue. in any case, boiling works for all pathogens....

Cooling boiled water doesn't necessarily take hours. Once, bike touring in the Black Hills, SD, I was descending a broad, rural valley with a lively stream - thinly populated with live stock. I boiled waiter, put it in a canteen, placed the canteen in the babbling brook, boiled more water; by the time the second pot had boiled, the canteen had cooled very nicely.

Doesn't one usually bring water to a boil when preparing the vitally essential tea or coffee?

Yeah, probably the same here in Wales. And certainly have in the past drank direct from streams and reservoirs here without treatment, with no ill effects. Though we have a lot of sheep.

Open fires are bit frowned upon, if not considered banned in large areas. So requires a stove and fuel of some kind, and for day out a thermos would suffice.

The Grayl does more, but is also more expensive and heavier than most systems.

I keep one in my pack lighter than water, MTC YMMV