Joseph,

> What is the best delphi data access components pack
> for Firebird (some pros and cons) ?

I think you will find that IBObjects is the most complete component set
and will prove useful for almost all "traditional" client/server
applications you are going to develop.
For less traditional environments, like multi-tier applications or
object persistence frameworks, you may prefer a thinner layer like dbX.

IBX should have the same application field as IBObjects, but they just
don't compare. I don't know of anyone that knows IBO and uses IBX,
except perhaps for limited budget.

I don't know enough of FIBPlus to be of any help recommending it.
The BDE is out of question, I suppose.
There are other libraries (like IBPP or ZeosLib), and then some more,
which I don't know about.
Ciao
--
____
_/\/ando