I'm going to hijack a bit since I've never used Mantano...
How fast is it? In my experience:
- Aldiko has been pretty quick and renders very accurately. It doesn't include any annotation support, but it supports multi-level Table-Of-Contents (although always expanded)
- Nook for Android used to be slow and render every time. The new version is slow to open the first time but very fast after that ... if it loads (very large books just fail to ever open). It renders accurately and supports multi-level TOC (although always expanded)
- CoolReader is very fast but renders poorly. The multi-level TOC support is beautifully done. It does not use Adobe's page numbering formula, which is a bummer.
- Nook Color renders quickly and beautifully. It also annotates well. It totally lacks multi-level TOC support and has no jump-to-page feature.
Can Mantano open password-based Adobe (i.e., B&N) books?
Call me cheap, but $7.49 is past my impulse-buy threshold and Google's 15 minute refund window isn't enough to come to a solid judgement.