CGI....
I own an Aerobird and have flown an SS several times. I really like the SS...tons of fun. I absolutely love my ABCas well and have no regrets buying it. love my Aerobird! The X-port and 3-channel controls add a ton of fun to this plane. You will have very little problems jumping from a Firebird to an Aerobird.I really think that the SS and ABC are 2 different types of planes and not necessarily fair to compare each other with. Comparing the Aerobird and T-Hawk would be closer comparisons.
I do really enjoy flying the SS and will most likely buy one once I do make the next jump to more tradtional gear. Many people do not like the fact that the ABC electronics do not transfer to another, I wasn't too happy about that either. But, this has allowed me to step back and really research and try different radios while learning how to fly @ the time. Instead of rushing into radio gear I might not like because I couldn't wait to start flying, or buying a radio from a guy because" it's a good one", I am really looking and saving for a more expensive multi-model digital radio. Again, I can afford to sit and wait and research while I am actually out learning how to fly because my ABC is so inexpensive. And, when I do step into another plane my ABC won't sit @ home due to it's having the X-Port on it. I can drop things from the ADM or dogfight other ABC's and FIghterbirds with the Sonic Combat Module. That is alot of value for your dollar.
Personally, I think you will not go wrong either way. Both of these planes are fun. They are fun in different ways:
The ABC is a fantastic flyer.It can be had for little money and adds the value of the X-Port modules. Plus, this little can flat out move! It can fly fast or slow. It also is extremely durable. Keep this in mind when people talk about crashing their ABC vs. SS. The SS doesn't fly very fast, so it doesn't crash very hard. I see alot of "I crash mine all the time and a little Epoxy and she's back in the air!" postings...this is true also of the Aerobird. Except the Aerobird flies faster, therefore crashing harder. But it endures them just fine.
The SS is a more traditional setup. However, it is super stable in the air. It is supremely responsive. A simple joy to fly. Which can be said of both planes. Plus the electronics are transferrable...major plus.

Both of these planes can be flown to great heights. I have personally taken my ABC by rough estimates about 400ft. That doesn't sound high....but it is when you are still kind of a beginner. I Have watched as a guy took his SS to almost 1000ft. Wow.

I only comment about these 2 planes because these are the only ones I have flown more than once. This is something to keep in mind when someone bashes one plane or the other. It also seems that there a bunch of folks who bought the ABC as their first plane, then proceeded to try to teach themselves flying with bad habits. With some mild help from an experienced flyer, any beginner should be able to handle the ABC just fine. You are going to be fine because you flew the Firebird. I can't tell you how many guys took the sticks of my ABC and went" wow!" as they were surprised @ how easy the ABC was to fly.
I hope I didn't just confuse you or cloud the issue more, but the truth is that this is all subjective. I can only be objective about my personal experiences. I won't bash the T-Hawk or any other plane in comparison, such as the EasyStar, because I haven't flown one.
Bottom line:
You won't go wrong with either choice. They are both fun and have their positives and negatives.
Good luck!
Have fun!

Shane
....now where did I leave that epoxy?