They are definitely an upgrade to the SE215, but they are also very, very different. SE215 is a "warm and sweet" kind of IEM, its tonality is a bit warm with forward mids and emphasized bass; the TF10 are V-shaped, and rather bright with much more and better extended treble, as well as punchier, more extended bass The bass sometimes sounds shallower and less "full" than the SE215 because it is a BA based earphone and has a midbass hump, whereas the SE215 emphasizes the whole range of the bass spectrum until it rolls off (around 22 hz according to Shure's specs, but I would say closer to the 25-30 hz range), but I also think it goes deeper and shows better detail in lower bass. In general the TF10 is a noticeably more resolving, more detailed phone. The midrange is brighter and clearer, but a bit glossy and not as forward and full as the SE215. The TF10 has a wider soundstage with better imaging and ability to contrast. I will say that the TF10 sounds a little hollow and is more revealing next to the SE215, which is a hinderance on some vocal tracks, especially the ones that aren't impeccable recordings; I prefer the SE215 for Amanda Palmer, Alanis Morissette, Bob Marley, Sublime...the TF10 has more midrange precision and detail, but it's also glossy and a bit recessed (though not horribly so), and detail isn't everything. I think the SE215 sounds more "real" on most vocal music.
The short answer: the TF10 is definitely an upgrade to the SE215 in terms of overall quality, but it is not a direct upgrade, because the overall sound is a very different one. If you want a triple driver monitor that is a more direct upgrade, try the UM3x. It's bass quantity is noticeably less than SE215, and close to TF10 but with less punch, and more body and decay. It has mids that are forward and just a bit warm, and similarly laid-back treble, also like the SE215. When I heard the UM3x, it was what I had expected the SM3 to be (although I like the SM3 for entirely different reasons).
