MTK chip based phones are still a No-Go for me. In the recent past there were a lot of issues with GPS & Bluetooth components and they also didn't use to roll out any updates, so it wasn't possible to upgrade MTK based SoCs to Android 5.x for quite some time. Nowadays they release updates for their chips much quicker and it's possible to run Lollipop on those devices. Nevertheless they still got a lot of work to do to catch up with Qualcomm. Just my 2 cents.
The 2014 model sold in germany is already equipped with an dual SIM slot. More onboard memory might be great, but an SDcard will also do it's job if you run low on space, thx to the changes to Android 5: http://www.androidcentral.com/lollipop-brings-changes-way-your-sd-card-works-kind-youll
A small technical change between MotoG (2013) and the MotoG (2014) are the RAM modules being used, they got upgraded from LPDDR2 to LPDDR3 RAM.
As a modder the MotoG is the 1st choice for me, simply because of AOSP ROM, the good availability of source codes and because Motorola got good dev's around (...although they are acting sometimes like: "Let's do this -> Leeeeeeeroy Jeeeeenkins" )
Personally I'd be more than satisfied with MotoG's HSPA+ (21,1 MBit/s) support. LTE is currently only available near bigger cities in germany and you have to pay more money per month for you mobile phone tariff.
In the future, the OnePlus won't be shipped with CyanogenMOD any longer, but with their own one called "OxygenOS". They hired some devs from Paranoid-Android project: http://www.heise.de/newsticker/meldung/OxygenOS-OnePlus-spaltet-Paranoid-Android-Entwickler-2553555.html
As you know for sure, there are different versions of the Y300 (Y300-0100, ...-0200, ...-A1, ...J1). Huawei never released the kernel sources for the Y300-0100 model, neither did they provide the source code for the ATH6KL WiFi module.
I've been regularly running into different kinds of trouble. The MSM7627A platform seems to be doomed
Well, 1st of all the Moto G 2014 is a nice low-budget phone, which is definately better than a G510/Y300 and worth to upgrade to.
Nevertheless ... before I even consider buying it possibly, I will examine the kernel and take a look if it contains the same Qualcomm rubbish, than other MSM-3.4 kernel got. In this case I will wait for a phone with 3.10+ kernel.
Android Lollipop got already released for the Moto G 2014 in some countries. I saw some videos on youtube. However they were still running with an 3.4.42 kernel
EDIT: after all those work on the linux 3.4 kernel and those things I've seen, I'm really addicted to the higher version kernels . MSM-3.4 kernels are crap
I've dropped the developement for this device, since it isn't worth the time and effort. The more time you spend developing, the less you see any light at the end of the tunnel.
I'm waiting for an affordable device, running on an Linux 3.10+ kernel and with Android 5+ on it. Kernel development for 3.10+ kernels is more straightforward. Devices being shipped with such an kernel will show much better performance and drain less battery, then any device with equal hardware running on a 3.4 kernel.
Currently only the Nexus 6 would meet this criterias. But it's too expensive, yet. Hope more devices will follow with affordable prices.