Pros:
Can be upgrade to your existing engine...

Cons:
- lots of paper works
- baka di sariwa makuha mong engine (lalo na pag surplus)
- baka di mapagana lahat ng sensors (lalo na pag EFI)....
- gastos!

Basta, kasama dapat sa deciding factor mo is dapat you are ready to take the head ache which comes with it, or head ache that might come by in the future (usually, mga di matono nang maayos na mga EFI engines bacause of faulty wirings or sensors na di gumagana, at walang makitang kapalit)...

I'm basing this to my experience.... I've done an engine swap twice with my current vehicle!