The first thing I want to mention is that the ear piece is supposed to be adjustable but it isn't.  I've been sitting here for 10 minutes trying to bend them and they don't bend.  If I keep trying I'm afraid I'll break the frame.  This frame is supposed to be bendable at the earpiece--it even says so on the Tifosi website (they have a little video up showing it bend easily).

So forget about getting a custom fit at the earpiece--it isn't happening.  However, having said that, the Slip does have a nice wraparound fit anyway and will stick to your head reasonably well.  They are also lighter than they look and they look pretty bulky.  In fact they have such a large and aggressive look that they are probably best suited to athletics or driving (unless you like looking like the Terminator).  The styling of these isn't going to work well for everyday use.

I added stars for the lenses.  It comes with 3 interchangable lenses.  The smoke colored lens is polarized and helps make for a very clear view of the road when driving.  The yellow and pink lenses are for low light conditions and can actually help to brighten a trail a bit.  The lenses are really nice and it a shame that the frame is so thick and large (though not heavy).

The specifics of what I got follows (Tifosi has a lot of different styles, be careful):

Model: SLIP
Color: Matte Black
Style: T-IP361
Frame: TR-90