I bought my MPP PIP-2424LV-MDS from MPP through eBay. I have had no issues with it. The problem is that there is a lot of copy cats out there and you can't tell them apart from the MPP company unit. When I bought mine, I didn't know any better, but I'm pretty sure its the real deal.
MPP recommends that you buy directly from them, although it might cost a little more as it is not a knock off (copy cat) unit.
Over the last couple of months, on my workbench, have been running my 2424LV through lots of different tests and playing around with the many options and setting. So for every test has passed. - I know that sounds stupid to do all that testing, but as a retired engineer, it is in my blood and nature. And through all this testing, I created a dynamic simulator in Excel. Now I can run the simulator for different scenarios and test it on the workbench. - I haven't bought my expensive Lithium batteries yet, so I have lots of time to play with it on my workbench.