you can use either one of these three. As you know, support can be obtained for all these models. If you prefer to stay with us, choose Medion. Medion X4545 is an excellent choice if you can buy it at a reasonable price. You may run GoPal 6.1 V 94809 with all features.
One map is just as good as the other. If I would be you, I would buy the x4545 for Euro 70, which I consider a very good price for a device which has been used one year only. If you can ask the seller for the original invoice, you still have 1 year of guarantee left, if bought at Aldi even 2 years. That sounds like a good deal. If you don't take it, somebody else might.
It's still a good deal. Almost all "good" second hand Medions will cost you around Euro 70, no matter you take a P4440 or X4545 or equivalent.
Checking your link on the comments, does not confirm 90 % negative. From my point of view, the x4545 is a reasonable device, having the latest WinCE 6 as operating system and featuring a nice 4.7" screen, what else you want for a moderate price. Up to now there ist no limit on GoPal Versions you may run on this device.
If I would be you, provided you need a new device, I would buy and update it. Consider, the "X" series is the most expensive offered by Medion.