Pro,
Simple enough to be friendly to program.
Cons,
$$$$$$$
So simple that many features on the stock one aren't there.
$$$$$$$
If it dies, you sit where you are till install something else to get home
$$$$$$$
No self diagnostics
$$$$$$$
Trash a stock ecm and for $25 you can get a spare, or even carry a spare with you.
You can get DirectScan and datalog a stock ECM
For 009s like you have no driver change needed
If you go to large injectors then add 120 or so bucks to make the stocker race ready.
If you don't like chip burning
And don't like the MAF go ME. And that gives fuel and some timing change ability.
You like MAF drivibility then a Translator Plus.
Rumor has it some stock ecm'd cars were running well at Bristol.
If you want to learn about chip burning, and then the world is your's. The GM ecm is fully hac'd, and it holds no secrets.