Rants. Difficulty To Learn ETL Tools?

Dear Experts,

I've worked with Oracle since 1995. I have gone
very deep into many of the Oracle features, including
sqlloader, and export/import. And I've done data
modelling even longer.


At the same time, I have done ETL since 1995.
Although, at the Proc, and PLSQL, sqlloader, level.
Map the data. Take data from the source, do any
modifications/transformations that are required,
and insert or update. Easy. The hard part is
determining the mappings.


But I have not been given the opportunity to
work much with ETL tools such as:
Informatica, DataStage, Ascential, Ab Initio

The little bit of experience that I do have,
showed that Informatica was -incredibly- easy to use.
It's a GUI. It's SUPPOSED to be simple!!!


I have missed out on a number of opportunities
because I didn't have a few YEARS of experience
with ETL tools. Which seems odd, because the
tool looks like it requires a max of a week to learn!


Just how difficult are these ETL tools to learn?
Especially if you have already been working with
Oracle, and doing data mappings and loads since 1995?
I'm thinking that it can't be difficult at all.

When you search for newsgroups, there are no newsgroups
for these tools. Although the companies who make
them, might have their own newsgroup.


There are also not many books on these tools.
If you search for books on Oracle, or SQL Server,
you will find a lot of very big, and detailed
books. But there is next to nothing specifically
on the various ETL tools.

Any certifications for any of these tools look
to be much simpler than Oracle's.


To me, the real issue is the mappings. If you
come into a new environment, the data mappings
are completely esoteric to those systems.
No amount of experience with an ETL tool, or any
tool, is going to tell you what the mappings should be.


Questions:
- Just how difficult are these ETL tools to learn
for an experience Oracle pro like myself?

- Other than a GUI, making everything simple to use,
just what are the advantages of using ETL tools?

- what built in functionality do ETL tools
have, that can't be done in PLSQL?


Thanks a lot!