I recently took the time to research options and install a Biesemeyer 30" Commercial fence on my Delta Contractor's Saw. A few notes might be of interest to woodworkers thinking about such an upgrade or ready to install.
Why the Biesemeyer design? Push sideways on the fence near its far tip. Rock solid. Biesemeyer's ads claim 1/64" accuracy, but these fences are much better than that. Calibrate it with a dial caliper or good hook rule. Other fences have more bells and whistles, but I wanted the best fence for the normal rips that comprise 95%+ of my fence-guided cuts.
Structural & installation advantages: Most aftermarket fence designs depend on the strength and/or straightness of the table and right extension wing for accuracy and support. Some also depend on perfect front and back rail parallelism for proper locking. The Biesemeyer, and a few other designs, don't have these faults. Easy installation and little maintenance.
Why the Biesemeyer brand? There are many clones, each with differences. I looked closely at a Jet Xacta Fence. It's solid polymer faces make it heavier that the Bies, it has adjustments for perpendicularity, and the guide tube is completely painted. Bad decisions. The extra weight seems cumbersome, the adjuster feet don't glide as well as the Bies fixed pads, and unpainted guide tube strips on the Bies make it more accurate and easy to move. They've been doing this for 19 years.
The Bies comes with an "L" shaped piece of thin particleboard to help set the front support rail. I made a pair of similar shapes from 3/4" MDF, clamped them to both the support rail and table, and was ready to tighten the bolts. More brackets helped back rail installation as well. Front rail "L" depth = 2 55/64". Back rail "L" depth = 2 27/64".
Right wing: You want the wing to be very stable. I made mine out of seasoned MDF. The finished wing (except for the plam top) got a coat of polyurethane to seal out humidity changes. I was careful to make the wing the exact same width as the cast iron top. I fabricated it slightly oversize and took light passes over the jointer with the completed wing to fine tune the fit.
Bonus rip width: I reserved the ability to occasionally rip to 34" (for casework) by making my right wing 30" wide instead of the recommended 24". I set the Bies 4" less than my desired rip, clamp some scrap to the wing at the far side, remove the Bies, and rip against the scrap. This takes advantage of the fact that the fence is almost exactly 4" wide. The 30" right wing is flush with the guide tube, so my shop clearance hasn't changed.
I hope some of these notes help someone. I've been very happy with the fence so far, and plan to work a router base into the right wing soon.