I strongly disagree the standard in Britain is lower than Russia. I dont know who said that but I dont think they can possibly make a statement like that.
[...well for one, I believe they have different sty...

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OK on a serious note, Trinity, Guildhall, RCM, and (I think there's another top one in UK but I forgot >.<) are all very reputable institutions...Moscow is also very reputable and they all sit up there as among the most prestigious conservatories in the world. In terms of standards, well it depends on the teachers as much as the students - and I don't think UK lacks great piano teachers. [just bear in mind I'm not saying anything about UK piano students and UK conservatories "standards" ^^]
In the end, it's how hard you work that will determine how good you will become - not just because you go to a conservatory with a higher "standard" than another (...as long as you get a good teacher, you'll be fine!)
With that said, here are the people I'd study with, if I ever get to choose

For Royal College of Music, John Lill probably has the best reputation as a (well...visiting) teacher there. Gordon Fergus-Thompson is probably fine too, while I think of Dimitry Alexeev as more of a performer than a teacher.
For Oberlin, I agree with pianowelsh that you should consider Peter Takacs...I'd go even further and say he's probably the best teacher there - he taught Spencer Myer, who is probably Oberlin's most successful graduate in decades (or at least years). Alvin Chow or Angela Cheng is probably fine too, I guess.
For Glenn Gould School, John Perry and Marc Durand go without saying. As for Northwestern...well...I haven't heard of any of them, not that this means anything. If money is a constrain, Oberlin gets my nod for their excellent financial assistance. Otherwise...Glenn Gould!!!
...by the way, in what way does Yale not fit you well? Boris Berman teaches there, and he is good...