They (Mk. 5) also happened to be basically a generation behind everybody else in terms of pretty much everything, and NTX's kernels were *really* iffy at the time.
And yeah, one very visible consequence of that is that Mk. 5 screens are *really* slow
.
That's also one thing that's worrying me about PB, last time I checked, they seemed to be using fairly old kernels for no apparent reason, even on decently recent HW (f.g., I think they have a couple devices w/ an i.MX7D running on 3.0.35 o_O)...
And, yeah, as Jon said, Kindles are pretty much out, unless you're willing to basically forgo WiFi forever, and you manage to get one that can be broken in to begin with.