I really love biblatex, the only disadvantage is that it is not so simple any more to mess with the bibitems manually any more.
Here is a problem that caused me grief: I was asked to blacken out (nigrify) the identifying parts of self-references in a paper to maintain double-blind refereeing. When I used regular bib, I just define
and put around the text
\newblock. Not very elegant, but doable. (note that there are better ways of nigrification, see
Efficient ways to anonymize a document but that is not the point)
In biblatex, I can do the same, but things are much more tedious since the data is organized in a much more granular way.... very very tedious (I just did it for two papers and it took me more than an hour).
Ideally, I would like to just specify the authors whose citations I would like to nigrify and then in these bib entries the author names, the title, URL, and page ranges are nigrified e.g. by
\blackbox. But I would also be willing to do some editing e.g. by replacing
\blackentry could call things like
locally for nigrification. In principle biblatex should be uniquely suited for this; I just do not understand the code deeply enough to do it myself.