Huawei has been the smartphone maker I've been most impressed by the last 18 months. If only the software wasn't a huge letdown.

To be clear, I'm not here to rip EMUI apart. Again. Because collectively we've done enough of that. In 2014 it was annoying, but given the massive improvements made elsewhere, it was possible to let some things slide.

But that strong 2014 left us expecting a lot from Chinese manufacturer Huawei in 2015. As it turns out, it was more of the same. Great hardware, lackluster software. That is, until the Nexus 6P collaboration with Google. With EMUI replaced by Google fresh Marshmallow, suddenly we had what we all agree round here is the best Android phone you can buy. And it's got a Huawei badge on the back.

This all goes back to the first half of 2014, when the Ascend P7 launched in Paris and caught us off guard. The hardware was superb, with elements that could rival anything else available at that time. The software, then EMUI 2.3, wasn't great, though. OK, some of the unattractive stuff could be hidden, but things were happening that shouldn't happen.

At least one of those things is still happening today, as highlighted in our Mate S review.

Ascend P7

For 18 months now, Huawei's battery saving software has prompted buyers of its phones to close apps because they're excessively consuming power in the background. At times this even included Google Play Services, that's how bad it was. Things that are essential to the phone actually running now seem immune, but even the Mate S still does it. You have to tell it not to on an app-by-app basis. That's not how this works.

That's just one area of concern. But it's also an area of concern I highlighted in that Ascend P7 review the best part of a year and a half ago. We've been saying the same thing over and over and it's still there. Other major manufacturers don't employ the same tactics. Either fix it or take it off the phone altogether.

Others will criticize the visuals, the lack of an app drawer, the "iOS influence." I'm not actually offended by the looks at all. The Ascend Mate 7 was a noticeable step up from what came before with the arrival of EMUI 3.0. A much flatter style, more muted colors, transitions, themes, I actually thought it was reasonably attractive to look at. If you want to see your Google-flavored Android shining through, you'll be looking elsewhere, but the Mate 7 was, I hoped, going to be a turning point.

But even on the visuals, in places the 2015 phones took a step backwards. The white notification shade was now replaced by a blackened, translucent effort on the P8 and now the Mate S. Not horrible in itself, but when some apps, like Gmail, use black text, you see where we're going. You're almost forced to use a light wallpaper to make it usable.

Huawei Mate S

It's not all bad, far from it. For example, I love the Clock and Dialer apps and the Camera is done pretty well, too. I generally appreciate most of the styling. It's a big departure though from what a potential buyer may have used before. And that could be an immediate turn off.

But for us, it's the sum total of all the little annoying bits that make it hard to recommend an EMUI based phone. Notifications are still a mixed bag, though Android Wear support has at least been fixed, and the constant messages telling you something is draining your battery are infuriating.

But then comes the Nexus 6P. Honestly, I believe, Huawei's crowning achievement. Sure, the company isn't responsible for everything in it, but it's the one that put it together. Finally, it feels like all that hard work on the outside has been given something worthwhile on the inside. I do miss some of the useful added features that EMUI adds, I really do. But I really don't miss everything else.

I'm not here to say Huawei should scrap EMUI and go stock. Plain old Google style Android on everything would leave little in the way of manufacturer differentiation. Nerds care the most about the software, regular people just want a nice phone that works. If through being a Nexus partner, Huawei can learn to tone it down and reign in all the little annoyances across the board, we could be having a much different conversation 12 months from now. Stock-ish software with value added features, like those BlackBerry has done with the Priv, would be a happy mix. But above all else, we just want it to work properly. All the time.