i have a swift on one my rifles (don't recall exact model... it is a high magnification model w/ ao).
clarity... not bad considering the price. it is not a leupold, and don't kid yourself into thinking it is, but it ain't bad. you will notice that at extended ranges the resolution is really bad, and the ao is useless at all ranges.
eye-relief is ok. i would not stick it on a hard-kicker though.
repeatability/tracking... this is where it lacks the most... if you aren't one to spin knobs, then it will suffice.
overall, i would say it is a good buy for the money, but if you are into nice glass, then this one rates a 'don't buy'. i do a lot of experimenting w/ rifles, scopes, etc, and i picked this scope up just to see if it was as good as i've read on the net. it isn't, but you could do far worse.
when i first bought it (spring this year), i took it to the range, and put it head-to-head against my vari-x3, a vari-x2, a vx-2, a really cheap bushnell, and a tasco. the magnification is different than leupold's. i think a 15x on the swift was roughly equivalent to 12x on the leupold. it was not as bright and clear as any of the leupolds i tested it against, but it did better in all aspects than the tasco or bushnell. i would say it probably rates very close to a vx-1.