these are only my experiences watching various long arm configurations in operation.
4-link with tracbar: i run this setup. a lot of guys say it will bind, but with good flex joints, it works just fine. i run Johnny Joints and OEM bushings in all 4 arms. Road ride is far better than my old short arms. The huge improvement was out on the trails. it climbs way better, and the range of movement is excellent.
3-link with tracbar: pretty much the same as the 4-link. The only reason that i decided to build a 4-link was just in case one of the upper links fails. Yeah i know the odds of that happening are slim to none, but its just that added security.
y-link: havent liked it since day one. it unloads going up severe climbs, which usually results in the front end bouncing under acceleration. it ruins the oem axle bushings in no time flat too.