Lenovo has no presence in the U.S. for cell phones. The P780 doesn't support LTE, which is a big problem in the U.S. Because American carriers never built out well-developed HSPA+ networks. They put most of their energy into skipping ahead to LTE. So the differential between HSPA and LTE is a lot bigger than in Europe. Finally, most international phones don't support all the bands U.S. carriers use for HSPA. This makes the lack of LTE even more acute.
Non-LTE works just fine in the US for a lot of folks. T-Mobile's HSPA+ network, where quite of few Moto Gs will end up, is solid. Heck T-Mobile's non-LTE network is faster than some other carrier's LTE networks in a lot of areas.
Right, but t-mobile is pretty much the only carrier with a really solid HSPA+ network, and has a tiny minority of the overall market. I've got a Lumia 620, which doesn't do LTE, and it's really not great on ATT.
It depends entirely where you are. I've had T-Mobile since the original G1 (first commercial Android phone) came out in NYC and have had no issues. Service is a bit spotty on the train up to Albany/Rochestor, but it is with all the carriers. The only places you have trouble with T-Mobile is when you get in rural areas, which I usually don't. The one exception is part of my family we visit and only Verizon has coverage by them. In that case, I just switch to wifi calling at their house. Or turn it off for a while.
In the states, if you're obsessive about your phone being on every minute of every day (and, realistically, anyone actually that important... as opposed to thinking they are for their startup... is still forced to carry a pager), you basically have to go with Verizon. That's why I have a Verizon hotspot as a backup. Not as a backup for T-Mobile, but as a backup for Time Warner, since it goes down at least once a month for a little while and down for a full day every few months.
This is one reason I'm always surprised people buy anything other than a Nexus device. You have a new phone, and it's running an OS that's already a year old.
I don't know if it does, but I live in Europe so that is not an issue for me.
Does it run a modern version of Android?
4.2.1
Does it have a modern SoC
It has more than enough horsepowers for what I do on a smartphone. It's quad-core, as for details - I never bothered.
Is it widely available in the US? Can I get after sales support?
Again, I don't know much about US, but I would imagine that a big company like Lenovo would be present there in one form or another.