If Jamie really has continent busting options like he claimed the Scarab was giving him vs The Spectre, he should win.
Plus, the Beetle tore through GL shields and generally managed to come up with on the fly tactics custom made for each opponent, such as conjuring up energy attacks that hurt Supergirl, and creating a tachyon field to stop the Black Beetle from time jumping...
I think Beetle is the stronger suit, but Tony may still have the edge due to raw experience.
Though the scarab can hurt people like GLs and Supergirl, it didn't exactly inflict major harm, it just caused more damage than blasts of that power normally would.
This thread has popped up before, and at that time I was very quick to give Tony the win -- but since then Jamie has had some impressive showings that have made me question my stance.