To get specific, AC is built with Allen Bradley SLC500 controllers. These were great when they came out in the early 90s, but by the early 2000s, Allen Bradley came out with the Logix series controllers. There were (and still are) far superior in performance and user friendliness than the 500s. Biggest advantage is that it switches from memory based tags (ie you have a dedicated "address" in the memory that you have to use, it was in octal, not decimal numbers, so 10=8) to name based tags (ie you give each variable a name that you can easily remember). The ControLogix series (and its little sibling the CompactLogix) are just leaps and bounds ahead of the 500 series. After almost 20 years, this line is fantastic (the most common PLC on the market today). This to say that Allen bradley is phasing out the SLC500 line to get everyone on the Logix line. Hence the reason my company has so much business. If a part of that system breaks, you don't necessarily want to have only ebay to turn to in order to get your ride running again. It is certainly possible that BGW is phasing out all of the SLC (or the even older PLC5 series) run rides with contrologix. CP has been doing that over the past few years, using at least Consign and IOE, maybe others too. As to the point about my comparison to consumer devices, it is true that they don't fluctuate with the market like cell phones do. They run a lot longer than consumer electronics, but at the end of the day, they still wear out, just much slower. 20 years of use wears any computer, so it's not unreasonable to upgrade it.