I posted some impressions comparing the 1plus2 to the Senn IE800 in the IE800 thread. thought some 1plus2 owners might be interested in the differences I hear so I'm copying it here:
I got a pair of used IE800 yesterday and have spent a big chunk of yesterday and today comparing hem to the tralucent 1plus2.
First off, I really love the IE800.
Comparing these with the 1plus2, they both are excellent at detail retrieval, revealing subtle texture to instruments, placing instruments and vocals in precise locations in space. All the good stuff we all expect at this price level, these both excel at it. So, really, it's a matter of taste.
The IE800 have more bass. I didn't think it was possible to outdo the 1plus2 in bass quantity and still keep all the quality and detail but the IE800 do it. I know some people will think it's too much but I think it's enough bass to hint at the type of body impact you get with speakers or maybe some larger headphones like the LCD2 or D7000 (although I think this bass is less bloated than the D7000). I like that part of the presentation.
The 1plus2 has a larger, slightly more out of head soundstage. Both headphones do a great job of precisely separating instruments and vocals but the 1plus2 spreads them out further in space and places the listener further back in the "audience". the IE800 has a smaller sense of scale than the 1plus2 but still has a very good IEM soundstage.
The IE800 mids are more forward and slightly more lush. The 1plus2 mids are a bit drier and slightly further removed from the mix (see comment about soundstage above). The IE800 mids are more involving for me. Particularly for my female vocal "go-tos" of Neko Case and Loreena McKennit. There's a bit more body and lower mid emphasis with the IE800 compared to the 1plus2.
So it's a bit of a tradeoff here. more intimate mids and smaller soundstage or drier mids and more expansive soundstage. they both sound great with different songs.
regarding sibilance, neither one is sibilant to my ears but I'm still trying to suss out the differences. on most songs I have the IE800 has less volume with the treble (cymbals, most notable) and is less sibilant with my test songs buuut, there were a few exceptions where I found the 1plus2 to be smoother and the IE800 to be a little harsher. I'm guessing this has to do with the narrow peaks and valleys in the IE800 FR in the higher frequencies. Some specific instruments that work in the higher frequency ranges might be a little harsher or more mellow than others on the IE800 if they're separated by a few Hz whereas they seem to be more even on the 1plus2.
I'm going to keep listening to both of these for the next little while but my gut feeling is that the bigger bass and more lush mids of the IE800 might sway me more than the larger soundstage and more even (but still elevated) treble response of the 1plus2. It doesn't hurt that the IE800 are smaller, easier for me to wear, and less expensive.
Oh, and regarding comfort. I wear the IE800 down, as I prefer to wear earphones, and have not had comfort issues. I'm using the circular medium sized tips and they're angled upward for a good seal/ The cable is microphonic but not as bad as the stock 1plus2 silver cable (which is why I use the heir magnus cable with the 1plus2, which is better than the IE800 cable in this area). I can hear the IE800 cable if a song is very quiet but at normal listening levels, I can't hear any cable noise.
Hope people liked the impressions. they're both great IEMs. Anyone who might consider themselves "refined bassheads" deserve to try the IE800 out.