I use tadalists all the time for making one-line notes and putting down ideas. Like, I have a tada list called "Ideas" for startup ideas and another one "Articles" for stuff to write about. 99% of the stuff I want to write down fits this idiom well.
Very rarely I want to take multi-line notes, in these cases I use Google Docs, since I use all the G apps anyways.
Where does your stuff fit in? The ability to link to other entries seems pretty useless, or at least rarely useful.
After trying out the demo, it's better than G Docs because the interface is simpler. G Docs opens docs in new tabs/windows which is pretty annoying for smaller docs. If you add some kind of check-off bullet point capability to your lists (e.g. gray them out), then I could ditch tadalist and G docs and unite my stuff here. That would make sense.
You call it a "personal wiki" which seems like marketing speak for nothing, since the idea of a wiki is that everybody can edit it, but if it's personal, then it's really just a specialized HTML editor (?). Maybe you should just call it a "Notebook that just works".
UI bug report: when I click an entry on the left side, you flash it (in yellow) and then you scroll to it. But if it takes long to scroll there then the flash in unseen by the user. Scrolling then flashing may work better.