My 2 cents:
You're either a code monkey that is happy to get on coding your little part of the system OR you're someone that likes to/needs to see the big picture on whatever project you are working on.
Where I'm from (London), I have not once seen a job advert that mentioned SCEA or otherwise. Extremely rarely, do I see mention of other Sun
Java certifications other than the SCJP...and even then it's a minor consideration. In short, I wouldn't do SCEA for job prospects neccesarily unless you think you can use it as a negotiating tool for your current employer when it comes to salary review.
However, I realise in other parts of the world, certifications are treated differently. Also, in other parts of the world, using brain dumps etc. is common place and thus certification values are pretty worthless.
If you've been doing
J2EE for 3 years then
you should have more than enough experience to do the SCEA, that is if you've taken an active role and interest in the analysis and development of the projects you've worked on etc.
I've never done any J2EE or even Java professionally. I haven't worked in IT for two years. I passed part I of SCEA with 91% after only one weeks preparation using information from JavaRanch etc. I'm quite confident I can do parts II and III with little trouble.
In summary, I wouldn't do it for career purposes (though it won't hurt) but rather do it for yourself. Perhaps to solidify your professional experience and bring all of the pieces together. After completing it, you will know that you have the knowledge you're "supposed" to have which gives you a good grounding and even perhaps some more confidence to call yourself an "architect" than you might have had before. It will probably turn out that you knew more than you thought.
Good luck.