Those actuators look very similar to Firgelli's so I would be surprised if they were any stronger/more durable. I see they do offer some different lengths though so that is interesting(i need 75mm for my Bruder 320 and they offer it) Firgelli has some planetary actuators out now which are much more powerful. The downside is that they are running the same size shaft as the regular ones so I'm not sure if they stand up much better. They are also much bulkier. I got one of the prototype units months ago and they are very strong. Another positive is that they don't freewheel easily like the regular ones. I didn't have any projects that it would fit into at the time so I haven't been able to "mileage test it" so to speak. Might be worth a look though for certain projects...
http://www.firgelli.com/products.php?id=56