[hieronymos]

I bought the Kobo Vox for it's screen and have to say I haven't been disappointed at all. Granted, I do have a little backlight bleeding, visible on pure black backgrounds, but it excels in direct sunlight. I love my balcony.

As for that endless processor myth:
You cannot compare ARM platforms by the Hz of their processor. Say, you have a PC with a 3.2 GHz Quad Core that you compare to a PC with a 3.2 Dual Core. You'd say, number 1 is faster. But what if number two has a graphics card? Then it really depends on the application you use. Can you even name 5 applications on Windows that are capable of using 4 cores at the same time?
I won't even dig into cache sizes and other factors.

I happen to have read a lot of documentation on the platform of the Kobo and there are 6 or more different processors; the plain CPU, a video processing unit, a graphics processing unit and a few coprocessors that take care of the rest.

So now a concrete example: I have a Motorola Charm, with a Texas Instruments processor at 720MHz. And the Kobo at 800MHz. You'd say they should have comparable results in a benchmark.
The best results, with Linpack:
Kobo: 13.9 MFLOPS
Charm: 5.6 MFLOPS

How do you explain that? No idea. Granted, the Charm doesn't have JIT but that accounts for maybe 10%. The frequency difference is another 11%. Where do the other 227% come from?

Android is very optimized for these platforms that have different processors. Which also means that it relies on all the different processors. The problems the Kobo has, sluggish UI, waking from sleep, unimplemented CPU scaling (thus battery life), occasional freezes when turning on, all point to a graphics driver problem. OpenGL and proprietary AMD drivers do not always play well together. Just wait for the update.

Of course, this doesn't mean that the Kobo performs necessarily better than the playbook. But how would you tell by looking at the specs and throwing frequencies around?