I agree with Lorne on that comment.
But back to the subject of the message, "Best US cellphone network?".
I think the correct answer is that there is NO "best" network (or even one could say good). There's just the "less bad" networks...
My company issues my phone and we're on AT&T (iPhone 4) and have the 4 GB/tethering plan which is nice, though I'd never pay the bill for that one myself. AT&T has a nasty habit of showing 5 bars on the phone while you're on a call, dropping you off the call, while still showing 5 bars...
For my wife, we went with Virgin Mobile's $40/mo (1200 min, unlim Internet,unlim texting) plan, though that price of course has now gone up ($45/mo now, and throttling after 2.5GB). I think we're still grandfathered into the older rates though. She has the Samsung Instinct (only Android phone avail at the time) which is ok, not great.
But saved about $80/mo compared to what we were paying with Sprint for the same service (ok yes, unlim calls on Sprint, but she rarely exceeds 1200 minutes anyway).
Virgin Mobile uses Sprint's CDMA network (Sprint owns Virgin Mobile USA), so same quality calls etc (Internet works a bit different with VM though since its double NAT'd, causes issues with PPTP connections). Only drawback is that with Sprint you can roam on Verizon's network when outside a Sprint area, with VM its Sprint's network only - no roaming. Hasn't been a problem for us though.
Also if you're thinking about an iPhone, note that the Verizon iPhone still doesn't support simultaneous calls and data (and I don't think any other CDMA phone or carrier today does, though supposedly Verizon is upgrading their network - don't think the CDMA iPhone is capable of this anyway).
This may not be a big deal for those using an iPhone for personal use. But for business, I LOVE being able to tether my laptop or iPad to the phone while on a conference call, especially when out of town. This for me is a MUST have.
If the next iPhone supports LTE and Verizon's network - then hopefully this would be resolved.
BTW - other thing to note in the USA is that 4G is NOT 4G...
4G could mean a technology ahead of 3G (Sprint (WiMax) or LTE (Verizon)) - though not 4G by the standards bodies definition, or it could mean "slightly faster 3G using 3G technologies" (TMobile with HSPA+, and AT&T to some degree with HSPA+) or it could mean "plain old 3G" for cases where the vendor doesn't have any other advanced technology (AT&T in areas where there is no HSPA+).
So 4G is strictly a marketing term in the USA that has NO meaning (while Sprint and Verizon blurred the lines (WiMax and LTE meet most of the 4G qualifications but currently don't offer 100M speeds)), TMobile was the first to blast it away by deeming HSPA+ (a "3G" technology) as 4G. AT&T then took this an ran with it deeming the standard 3G to be 4G on phones they want to market at 4G.
As the British would say "Brilliant!".
Oh, and if'n one thinks that LTE in the US at least is closest to true 4G (which with Verizon I would tend to agree), consider MetroPCS's recent announcement of a full 4G LTE network that reportedly:
"The wireless carrier's average speed is about the one of a moderately fast 3G network"
And one wonders why there is so much consumer confusion in the US??