A lot of knowledgable people will tell you that EFi is faaaar more reliable than carbs will ever be.
I know that doesn't help in your situation since you can't get the thing to run in the first place but if it was me I'd be sticking with the EFi. It took me the best part of a year to diagnose a swapped sensor plug but I wasn't really trying. The car just plain refused to start when hot even though a gem from cold. When I went at it properly last month it only took minutes with the help of RAVE and the ETM.
If I was in your situation I would start from scratch in a systematic fashion checking every single part in order starting with the order of the spark leads all the way through to the wiring of the sensor plugs. You need 4 things to be right, spark, compression, timing and fuel. Isolate and prove the integrity of each before you replace the EFi.
It would be a killer to change over to carbs to find it still didn't start and you're actually now in a worse situation since you don't know if it's still the original problem or someting wrong you've done with the carb set up.