I have been using mine for 3 years and have never gotten sick, my only small complaint is if you get bugs/dirt you still drink those unless you fill your container through a filter or sock.
I started using the Katadyn BeFree water bottle with filter this summer while bighorn sheep scouting and really liked it. It filters super fast, doesn't clog, and virtually doesn't add any more weight to my pack. The bag with the attached filter is actually less weight and bulk as Nalgene bottles. It also saves having to haul water around if water sources are available....merely fill up the bottle and drink as you need water. Another advantage would be that it filters out any debris or mucky water.
I've been running one for a few years now...I pushed my luck last year with chunky bits in the water and copped a dose of giardia. I've bought a pre-filter as I don't want to repeat that again.
The steripen is all good and dandy until the light can't penetrate inside the chunky bits.
I like mine for solo trips. For more than one it is a lot of stirring time. I prefer a gravity filter for a group.
Batteries - mine doesn’t eat them but have some spares. Also use lithium in case it gets cold.
Chunky water - more than just gross, the light can’t penetrate small solids so chunky water is not going to be as clean. Coffee filter or a t shirt or bandana is enough to avoid chunks.
I have the classic model, does great on batteries, been using it for 3 years.. I'll probably start pre filtering though, last season we had red little swimming things in there and my wife wasn't to fond of that lol
Mine goes a full season on batteries, but I swap them every 6 mos. or so. If the water has “stuff” in it, I pass it through my bandana/shemagh first. Never had a problem.
For camp water, I use aquamira tabs and let it get the contact time it needs.
Been using one of one type or another for 7 years or so. No complaints. I use a 1 micron diesel filter / sump sock as a scoop/prefilter works awesome and weighs nothing after cutting and removing the metal ring
Sumpsock | Polyester Felt Filter Sock | 1 Micron Rated | Signed for Strength | Aquariums, Koi Ponds, Pools, Reef Tank | 4" x 8-1/2" Size https://www.amazon.com/dp/B079HD777W/ref=cm_sw_r_cp_api_i_5IFuEbHQTYT8X
I took my old version back to REI due to battery thing and got a different version (greenish instead of blue) works great 5 day trip in temps to 0 and batteries still rocking
Just bought the Ultra after 4 years of the Adventurer. Never any issues. I use a bandana as my filter, simply put it over the top of the Nalgene and fill. It’s been a nice change from the pump.