The N900 should be able to run anything the N8x0 can run.

In terms of chroots there are three differences between the two devices that might be relevant:

1. The N8x0 have even older kernels. Afaik there is a range of 2.6.21 to 2.6.23 (correct me if I'm wrong), while the N900 has 2.6.28. While in theory this would be an advantage for the N900, it doesn't matter from a practical POV. All of them are outdated beyond hope. 2.6.32 would be a slightly different story, because glibc still retains support for that due to some legacy RHEL version. But even 2.6.32 would merely delay the inevitable.
The lesson I have learned from the N900 (and probably some others too) is, that I will never again buy a device where I can't install a mainline kernel without losing core functionality.

2. The N900 (with KP) supports armhf. This doesn't actually boost performance, but it increases the range of possible candidate systems in chroots, because any armhf device can stiil run armel but not vice versa.

3. The N900's CPU is considerably faster. From today's POV it doesn't really matter, since it's the difference between "very slow" and "incredibly slow", but for some applications it might still make the difference between being usable and being not.