Go with the FiberPlus pads if longer wear is what you're seeking. The standard FiberPlus pads are manufactured with a special elastomeric binder material that helps them hold up to carpet cleaning. Typically they last about 20% longer than the FiberPlus Max pads, which doesn't contain the special elastomeric binder.
On the other hand, even though the FiberPlus Max wear faster, they also scrub faster. So while you may lose out on some pad wear, the increased agitation of the FiberPlus Max adds higher production to the bottom line. But like I said, if you're looking to obtain the longest lasting pads - you'll want to continue using the FiberPlus pads.
Normally FiberPlus pads will last around 7,000-10,000 sq ft per pad installation. Whereas FiberPlus Max normally top out at around 7,000 sq ft. Of course, your mileage may vary due to coarseness of the carpet fiber, and how slow or fast you run the scrubber. (It sounds like your needle felt carpet can be a challenge)
By the way, run the pads till they wear very thin before replacing them. Also, try to avoid removing the pads from the pad driver unnecessarily - since that will tear at the pad and weaken its grip on the driver. Simply run them till they're approximately 1/4" thick - and then dispose of them and replace with a fresh pad.
The FiberPlus pads are designed for carpet cleaning. They produce the proper degree of agitation for cleaning carpet. They're also designed to last as long as they possibly can so that you can get the most out of your investment in carpet scrub pads. Hope you enjoy using them!
