Revisiting AT&T vs. T-Mobile

I have had about 6 month to experience T-Mobile both here in LA, around major cities in the US and Canada and in London (see my blog for the the switch experience).  The entire time I have done this, I have had an AT&T phone with me (I know, silly), but when I left the country, I would put a local SIM card in that phone (Vodaphone in London for example).  Some conclusions so far:

• T-Mobile is significantly cheaper than AT&T for international travel.  Even after they responded to losing customers for international travel, implementing a plan similar to carriers in Europe ($10 per day but allowed to run off the normal monthly data plan), T-Mobile ends up being $100-200 cheaper per trip for me.
• T-Mobile lets you tether in their unlimited plan, AT&T does not.  #FAIL for AT&T.
• AT&T is still "faster" in most situations for downloads (i.e. trying to download the same video before a flight) -- even when both have same number of bars on LTE, etc.
• AT&T has significantly fewer dropped calls.  T-Mobile will has dropped my call with 2-bars in a plethora of situation.  Ironically, in these locations (often my house), I switch to the IP phone client Bria (app on iPhone) and the data carries the call better than the voice plan.

What would make me move "back" to AT&T?  They would need:

• Tethering for their unlimited plan
• Reduce or drop the daily international data charge from $10 to $5 or less.
• AT&T would have to stop "threatening" to reduce my data speeds to 2G after 22 GB have been used in the billing cycle.  Even though they appear not to follow-thru on my family, I cannot take the risk of need a critical file and having it take hours to download because they have throttled me on their "unlimited data" plan.

Stay tuned...