Good question, I recently saw on a DIY forum folks discussing the merits of linear or SMPS for Hypex NCore based amps. First of all my view is that the best sound from Hypex NCore NC500 modules is with the recommended SMPS1200A700.
A USA based company is recently offering a new range of multi channel NCore amps at around 200W per channel. A closer look at the spec sees they are using a linear PSU. So they must be NCore NC500 amp modules? Why only 200W? and why Linear PSU? With only using 200W per amp a smaller linear PSU can be used and offers a good solution. But to get the full potential out of the NCore NC500 would require a huge linear PSU (expensive) with large amounts of capacitance.
With SMPS and full 500W it would be to expensive number 1 and 2, space would also be an issue even if they shared 1 PSU between 2 NCore NC500. We looked at producing an 8 channel NC500 amp but we thought it to expensive and to large when using SMPS PSU. So its a balance of what the producing company can do easily and well, in the most cost effective manner. I guess an element of what the brand is known for comes into play. For instance, for us to design and produce a large high quality linear PSU would be expensive and time consuming. Luckily Hypex produce an excellent SMPS1200A700 specifically designed for the NCore NC1200 and the NC500 module. For us the additional cost and the performance it delivers out ways the cost and time of producing a linear PSU. There is simply for us, no point.
Our new multi channel amps based on the new Hypex NCore NC252MP and NC250MP have built in SMSP and will allow us to offer a very compact 8 way amp.
So to sum up it's really down to brand strengths, history and perceived product positioning. Ours is simple, the very best sound at competitive prices.
Just to put this in perspective our Abrahamsen 70W amp uses a huge 1000Va 100,000 microfarad PSU and weighs in at 16Kg.