Biber can only be used with biblatex. The traditional BibTeX approach with \bibliographstyle is incompatible with Biber. This means there is no moving from BibTeX to Biber without also moving to biblatex.
So your options are to use
- BibTeX with
\bibliographystyle,
biblatex with BibTeX, orbiblatex with Biber.
Using biblatex with BibTeX gives you the worst of both worlds: Some fancy biblatex features are only available with Biber, while most – if not all – drawbacks of the biblatex approach are still present if you use BibTeX. (For example in Biblatex: submitting to a journal it really doesn't matter a great deal whether you use BibTeX or Biber as biblatex backend: The publisher will still have to use a different workflow for biblatex bibliographies.) The development of new biblatex features generally assumes Biber is being used as a backend. Sometimes it is possible to implement some of these features also with BibTeX as backend, but it is not top priority to find a way to do that if it is more tricky.
It is true that Biber is generally slower than BibTeX and a bit more picky about your .bib files. I can't argue a lot against the fact that Biber is slower: I can only say that it is not necessary to run Biber every time you (re)compile your document. A build tool like latexmk will help you run Biber only if it is necessary. I see the fact that Biber is a bit more fussy about malformed .bib files as a plus, because in general Biber only complains about things that are wrong, i.e. that could cause trouble also with BibTeX, it's just that you might not have realised that there is an issue.
So I believe that nowadays the choice should be between the classical BibTeX approach with \bibliographystyle on one side and biblatex with Biber on the other.
My usual advice is that there is no reason to switch to biblatex (+Biber) if you are happy with what BibTeX (w/ \bibliographystyle) can give you at the moment. biblatex is generally not that well liked by publishers (who often have their own \bibliographystyles for BibTeX). Because it is still under active development it can sometimes be a bit of a pain if you want to use new features when you collaborate with others who are using older systems.
But there is a bunch of things that is so much easier with biblatex than with BibTeX: Mainly style adjustments, split bibliographies, on-the-fly data manipulation, ... If you need one of these features, then biblatex is usually your best bet of getting these things done.
bibTeXis sufficient for your documents, why not stick to it?biblatex?bibtexand friends still work for you, you should probably stick with it, especially if you submit your work to journals. Switching tobilatexwithbibtex(and nobiber) is in my mind not a good option.biblatexmeans, nowadays, also using Biber, as there are many features of the package that BibTeX can't cope with.