Ciao Guillermo
I did use the Whizlab for the SCEA part 1 and I found it pretty useful. I decided to buy (well, get my company to buy it for me..

) because I found it extremely useful for SCJP and SCWCD.
However for SCEA part 1 it is possible to do without it (I think) if you experience traverses the different aspects and topics required.
Personally my EJB experience wasn't great, same for legacy connectivity/applet security... so for those it really helped me.
Good luck
Beppe