Reviewed in the United States on July 10, 2018
TL;DR Decent improvement, especially considering the price has come down. It looks nice, the body is higher quality, but many of the new features have critical flaws. Still, best trackball on the market that I've found.
I love the M570 trackball mouse from logitech. I've bought 2 of them, and recommend them to everyone, to an irritating amount I'm sure. So, I was excited when my friend linked me that the MX ERGO was coming out, since there don't seem to be any real competitors to the thumb-trackball design style. Sadly, there are many design features that I don't believe are helpful, or missed the mark. I will list them to excess below, since I just got annoyed due to #7 as the last straw, and decided to rant here, the only place anybody might read about, let alone find helpful, such minutia.
The Good:
0) The mouse itself looks very nice. Replacing the blue trackball with grey makes it appear much less tacky. And, the material the body is made of is softer, and lightly textured, with a rubbery feel, that prevents hand slipping (Except for the left and right click buttons, which are the familiar smooth plastic). Clearly a higher quality build, with attention to tactile sensation and practicality.
1) It's very heavy, because of the new pad. One of the primary flaws with the M570 was the 4 little rubber feet on the bottom, that inevitably came unglued, and had to be re-improvised: so a full bottom, rubbery traction surface is very welcome. And it may be neat that it's magnetic, but the pad's weight is easily half or more of the whole mouse. What's more, you can remove this pad (again, it's magnetic), but you're just left with an awkward, round protrusion, which is impossible to balance on. I can't imagine using this mouse WITHOUT the pad, so making it removable doesn't seem useful in the least, except I suppose for removing and cleaning the trackball, which could have been accomplished with a button, or side access of some sort.
2) Return of the forward and back keys, quite welcome, good placement. They're longer and shallower than before, and seem to make a little click each time you rub your finger across them, which is extremely minute, but an annoyance nonetheless. All mice should have these buttons.
3) The scroll wheel. It's rubberized, with traction marks, to make it more reliable to roll, which is nice. It also has a left and right angling settings, purportedly for scrolling left and right via the wheel too. However, using these left or right scroll wheel clicks, WITHOUT also scrolling up or down somewhat, seems nigh impossible, and certainly isn't highly convenient. Most importantly, however, is that there is an excessive amount of slack on the normal scrolling function. It is extremely loud when it scrolls, and there are clicks during scrolling from the wheel, that don't actually register as scrolling on the computer, or likewise sometimes you can scroll on the computer, without having gone 1 full click on the wheel. I think the attempt at excess features baked into the scroll wheel has compromised precision for a key component of every mouse.
The possibly neutral:
1) Ball Inset. The ball on this one compared to the m570 appears to be slightly more recessed into the frame than previously. This may be good, to avoid it falling out with a simple bonk, but additionally, the hole underneath for access to remove the ball, is too tiny / too deep for a normal finger to reach through and poke out, for cleaning the rotation contacts from debris accumulation. I had to get a pencil to remove it, which is a small detail, but one more exercise in unnecessary added effort.
2) Contours. There seem to be even more contours to support the shape of your hand with this model, specifically at the far edge, where your pinky would reside. However, as best I can tell when trying to fit my hand to the curves as seem to be intended, it ends up tilted about 15 degrees counterclockwise to where my hand would normally situate itself. This results in the ball being at the very tip of my thumb, which prevents me from being able to move up very far, before having to reset my thumb's position; I prefer the ball to rest under just about the midpoint of my thumb's tip and it's first joint, which might seem picky, but what kind of review writer would I be if I weren't?
The Bad:
1) The connections button. I don't know how many people need to rapidly, and often, switch which device their mouse is connected to, without using the provided dongle. This key takes center stage, right below the mouse wheel, with big 1 and 2 labels to make sure you know which device you're utilizing a connection for. This key alone is questionable on importance of including, but there's no way anybody needs it to be as readily accessible as under the scroll wheel. It should, at best, be out of the way, on the side somewhere, instead of in a prime real estate location. Worst yet, this button is not available for customization, so you can forget trying to remap something useful there.
2) The new precision cursor speed button. I've had gaming mice, and having the ability to quickly switch from high speed to fine tuning is something I've missed sorely, so this should be a positive. However, the key is behind the trackball, making it extremely awkward to press, and requiring you to use the very thumb you need for mousing, adding a large delay, and a lot of excessive movement. It could have been almost anywhere, and it have been better placement. It also has a little light, to let you know you're in precision mode; I'm ambivalent towards this, since it would be hard to confuse which is which, due to the extreme slowness of it. Granted, I believe you can tune the ratio of the high and low speeds via the app, so this is adjustable as one may see fit.
3) The angles for the new pad aren't quite right. Obviously this will vary with different people's geometry and preference, but I assumed before purchasing that there was some incremental adjustment method for angles BETWEEN 0 and 20 degrees, but it is binary one or the other. I stay in 20 degrees, since 0 feels more like negative 10 degrees, but I wish there was a way to tune the angle to closer to a 10 degree mark.
4) The former spot for your own battery has been replaced with an integrated, rechargeable battery, with a forward usb port for charging. They claim it lasts for 4 months, but at that timescale, it's really beside the point, since that's basically never having to recharge. I always used my own rechargeable batteries, but this admittedly makes it that much simpler. If there become battery issues in the long run, then you'd have to replace the mouse instead of just the battery, but it's hard to imagine battery life for something so simple becoming an issue before any other of a number of factors would first.
Note: Battery finally stopped holding charge, requiring me to buy a new one. Granted, it lasted 5 years, but if I could've changed the battery, I could've kept using the mouse for longer.
