The ommission of a search feature within books is a major issue with me too. Had I known this feature was unavailable I might have passed on buying a Kobo Touch. However the Kobo developers seem open to adding features that we request and I'm hoping the SEARCH feature gets added soon. I suspect it has been oft requested.

Not sure why the Adobe ePub displayed differently in the Sony than the kePub does in the Kobo app. The problem I had with my book (see photo from earlier post of wide margins on a Sony 350) was caused by author/publisher formatting snafus. They used an antiquated CSS template that was never adopted in the ePub standard. That is not Kobos fault but the fault of the book publisher.

To test whether Kobo Adobe ePubs display well in non-Kobo readers would require more than one book as any book is subject to bad formatting. You might try downloading several free books from Kobo to see how they display and compare them to how they display in the Kobo app.