I recently purchased a Moto G (2nd Gen), so I thought I would share my thoughts about it from the perspective of having a Moto G (1st Gen) as well.
The battery is the same size in 2nd Gen and in 1st Gen and the display is bigger. Thus battery life is worse on the 2nd Gen.
The display is bigger, but it is not higher resolution. If you need a screen that makes things bigger then this would work for you. I was wanting to see more stuff on your screen, this isn't what you want.
The processor is the same in the 2nd Gen and in the 1st. The amount of built in flash persistent storage is half the size in the 2nd Gen. This caused me issues in upgrading. It couldn't migrate my data, since there was less storage.
It does have a micro SD card slot, which is a big plus, but I feel like the next iteration of a product should not have less storage than the previous. Also, 8 gig is way too little storage on a device today. A device should be usable by the average user out of the box without having to buy extra stuff as soon as you buy it. The argument that they were able to get the price of the device lower that way doesn't fly. I don't believe that flash storage is that expensive to cut into their margin on this device. I also don't find the device to be cheaper if I have to go buy more memory when I buy it.
On the same topic of needing to invest more money in the device, the device is somewhat slippery, just like the 1st Gen. It should either come with a case or be designed to not slip out of my hand when using it. It appears that they tried to put some sort of rubber coating on the back, but it has no grip to it.
The 2nd Gen has 32 gig SD card limit. Perhaps this is a limitation of Android, but 32 Gig is tiny considering the device has video pictures and music capabilities in addition to installing apps. Maybe it is a bit early to expect terabyte cards to be able to be used if you could find one, but I don't see why 128 gig is too hard.
One of the factors that drove me over the edge to get the next generation Moto G was that it had dual speakers instead of just the one. I thought that would make it louder. It is actually quieter.
The sound quality appears to be a bit better, but I really needed it louder more than I needed higher fidelity.