Away back (around 1977?), Bill Booth invented the 3-ring canopy release system. A quick, simple one handed method of jettisoning a canopy that effectively became (& remains) the industry standard. The size and relationship of the 3 rings was carefully calculated to produce a mechanical advantage of around 200:1. As equipment design progressed a 4th, smaller ring was introduced & this satisfied the demand for smaller, lighter (?) equipment. In particular, the "mini" 3 ring was applied to type 17 "skinny" risers which allowed the slider to be pulled down & stowed for extra performance.
Unfortunately "You get nowt for nowt" & the mini ring set suffered a loss of about 50% of mechanical advantage compared to the standard ring set. Still... That was the fashion - small canopies, skinny risers & mini rings - that's what the real canopy experts were jumping.
At this point I'm reminded of The Addams Family TV Series... An opening sketch where Gomez crashes into the house under a parachute & announces to the family & stunned guest that he's practising jumping with ever smaller parachutes until he can skydive WITHOUT A PARACHUTE!!!
Anyway. At present there are effectively 2 choices when ordering a harness & container: Standard rings which come with Type 8 "wide" risers, or mini rings with type 17 "skinny" risers. The second is the "performance" option.
The ideal option would be the standard ring set on type 17 risers, but most manufacturers don't offer this - probably 'cos no-one ever asks for it or is willing to pay the extra for it!
Anyway, the reason you see large ring sets on student kit is safety, the reason you see small ring sets on "experienced" kit is a mix of fashion & performance.
. 
