The internal resistance for this battery was too high for ...
925428
The internal resistance for this battery was too high for a battery that is supposed to be new. This causes a big voltage drop under load.
1249787
I purchased a total of 6 of these 3-cell 18650 battery holders. Three of the 6 holders did not work reliably, and the manner in which they fail could be a safety hazard. The batteries hang up on the plastic side walls, and the springs are not strong enough to reliably push the battery against the positive contact. If two or more strings of three batteries are used in parallel then there is a very real danger of intermittent contact, intermittent charging and high internal currents. By tapping the full battery holder on the bench it's easy to change the state of the battery pack from open to correctly contacted and back to open circuit again. Especially dangerous for portable equipment.
2523132
This battery has the highest capacity and reviews( number and rating for a replacement battery. The screw drivers could be stronger because I tried using the torx screwdrivers on my retina MacBook Pro and the drivers heads stripped and the screws didn't budge.
1616052
I bought this unit primarily for its temperature displays - inside and outside.

8 Months later... the outside sensor died. I thought it was the battery, and indeed they measured only .7V each. But, when I put in new batteries, it wasn't recognized by the display. After a while, I smelled a hot electronics odor, and the temperature sensor was very warm. The new batteries were already down. As an electrical engineer, I knew what had happened - the unit had failed in the summer heat.

That's discouraging. Something sold for outdoor use should be able to stand high temperatures. I would bet that the components of this are standard commercial IC's - which can only take up to 120F.
1538759
Batteries are kinda puffed up, as though their plastic cover was inflated.  As a result, they're a tighter fit than the stock battery.  I bit of extra plastic from the seams as well, but that can be trimmed with scissors.
4787059
The replacement battery matched the requirements for my T43 laptop.  Unfortunately the PC went wonky every time the battery was a part of the system.  Even with the charger attached, the PC crashed or froze countless times after swapping out the battery.  Much to my amazement, all of the problems disappeared when moving back to the original-yet-aging battery.  In the end, my solution was to stop using the battery completely.

The battery arrived on time and yes it fit properly, etc.  I seriously question whether the internal charging smarts of this unit is fully compatible with the specifications of my PC though.
3541702
My dog can move too much and the battery moves out of lock position just a little and the barking starts. They just are not as tight as the original batteries.
4656912
Too much power for what I was going to use it for, had to return it.
4256932
This was not the correct battery for my laptop computer.
660754
The actuator is misadvertised its actual inrush amp draw is significantly higher then the listed 4.6A Max. The motors internal resistance is 1.2-1.5 ohms which puts the current inrush amp draw @ 8-10A. Also confirmed with an ammeter & ohm meter. The motors resistance fluctuated when the metal case is moved drastically, which points to a bad winding/cold solder joint. It worked, just not as advertised.
1912423
Had to return because battery compartment was corroded with old batteries, this item was on special when I purchased so I don't know if they were trying to clear out old inventory, they did accept the return without any issues.
276762
Battery started blowing after a few weeks, it grew so thick that it did not fit in the phone, I was afraid it was going to explode
1548966
I would not rate this highly because I have already run into the same problem using these batteries with two different products. They are too big, and with both battery locations these could barely fit. The battery locations on my steam controller are too snug for these, and have already damaged (slightly) the plastic coating on two of the batteries, which is not ideal for a long life. The other battery location they we so tight the spring which is supposed to push the AA into the + connect could not, and I had to align them myself.
904582
Aside from complaints about short range, in trying to put a new battery in, carefully, I somehow managed to damage one of the battery contacts, bending it downward in such a way as to make it impossible to reinsert a battery inside the small plastic transport.  The tolerances are so tight inside that it could not accommodate the new battery inside the transport after the battery contact was bent downward.  Because the slot for the plastic transport is less than 1/16 of an inch, there is enough room to insert a tool to bend the contact back upwards, but not enough room inside to actually bend the contact itself.  One attempted battery change, and it was ruined.  I'm looking for a non-OEM compatible now.  Won't buy this junker again.  First disappointment with Olympus after an e-500 and an upgrade to the e-510.  Olympus shouldn't neglect these little products, but they did with this one.
3792703
I bought this battery as a direct replacement for my Garmin.  It was the proper voltage and amperage but I had to solder the old connector to the battery and the Garmin still will not accept it and shows a battery icon at the top right of the screen.
1520595
I wanted overkill and I got it!  I use my 99 RAV4 for a mobile office running a large laptop, printer/scanner, charging various things,  so I wanted a battery that could handle the load.  I also upgraded my 90 amp alternator to a 145 amp one (I also upgraded my grounds and positive wires from 4 gauge to 2 gauge.  I was tired of power issues and I'm sure I've solved my problem.  One last thing, I added a 50W flexible solar panel to the roof to keep things charged.
4539284
The battery that came with my phone holds a charge longer than this.