I went through this same argument with myself when switching from an 8 3/4.

I ended up with a strange housing, Pro HD center section, 35 splines axles and the strange rear brakes. I felt the 9" is more user friendly for what I wanted to accomplish. With the aluminum center and sheetmetal housing it is probably around 25-30 lbs lighter than an S-60.

Here us what I paid.

Strange sheetmetal housing with ends welded on - $525.00
Strange Pro HD center section with a spool, 4.10 gear, and billet yoke - $1245.00
Strange axles with bearings and 5/8 studs - $515.00
Strange rear Brake kit- $580.00

Total - $2865.00

I was quoted somewhere around $2000 for an S-60 with no brakes and a spool.

So all in all I feel like the price point on both of them is right around the same if you compare apples to apples.