[Device Reviews and Information] copperge:
Howdy bud.

I've been using this phone for about 6 months or so now and have a few different roms and the like. Phonememe has done a decent review of the three main roms for the phone on post #801:

Covers some features but I'll run over my experiences with battery life, camera quality and sound.

My Ecoo E04 came with stock Lollipop 5.0, so I decided to stick with this for a while The battery was okay. I expected a little better, but since the rom was quite heavy on ram, along with some overheating, I’d almost get a full day at medium usage. Stability-wise, I didn’t have too many issues with this rom other than the ram management, which caused the occasional lag.

I then moved onto Spacerom which worked alright but I noticed a couple of glitches (which I haven’t seen anyone else mention here so it may have been just me) such as screen flutters or .png buttons (eg the play/pause button in music) seemed glitchy. Nothing deal breaking, but a tad annoying for me. Performance wise it was pretty good, didn’t overheat as much, and as Phonememe stated, always had sufficient ram. However I found that the rom wasn’t completely stable (had a couple of random reboots).

I decided to stick with stock KitKat 4.4.4, which I’ve been using for a while now. I have had absolutely no issues with this rom at all. Stability is spot on, performance wise its great. I’d say the battery life is the best of the three. I’ve not noticed much overheating. So in terms of roms, for me at least, this is my personal favourite.

Overall, battery life can get you throughout the day at medium usage, I charge overnight and normally have sufficient battery by bedtime. Coupled with what you stated, removable battery, you could always buy a spare if you wanted to go down that road.

Quick note on the temperature, I found that after I got a case for this phone (flip case with a little clock window) the overheating was significantly reduced. Might be worth considering.

Another side note, from what I’ve seen there isn’t much potential for future development with this phone. There is a CM12.1 Rom out there, but apparently is isn’t stable at all and I’m not holding out on that changing anytime soon. I’m sticking with the Stock KK 4.4.4 for the long run really.

Sound

The sound isn’t great in all honesty. In my opinion, it’s a little quiet, and sounds a little “tinny” You can make it a little bit louder through “Engineer Mode” (EngineerMode >Hardware Testing >Audio >Normal Mode –Change Max Vol. from 144 to 160) but even so its not really built for playing music through.

Since mine is normally on vibrate, and for music I use decent headphones, this isn’t a deal breaker for me. That coupled with having Viper4Android installed, through headphones it works well. It depends what you are using it for.

Camera

As you said, the camera has mixed reviews. I myself haven’t had many problems with it. Nor have I noticed any difference between roms. I just took a test image, and it seems plenty clear to me. If you’re big on your photos however, you may think differently. Some people have commented on the images being grainy or not very sharp. I myself haven’t noticed any issues.

In comparison to the other phones you listed, my girlfriend has the P8000. I’ve not played around with it much yet but from what she has mentioned all seems to be smooth, with a good battery life, but it is prone to overheating.

I don’t have any experience with the others you have listed so my advice to you would be to consider the above, and have a read though the threads relating to the other phones and see what works best for you.

Since these phones are all on the cheaper price range, I’m sure they will all have their quirks and glitches along the way.

Good luck!