No Bronze Guides, Any Reason?

I run bronze Guides ,I've run steel guides ...steel guides last long for me... bronze are great too..they wear the valve stems less and have a diff expansion rate..people like them in hp stuff, stuff that is re freshed/machined frequently. I don't know what to tell you. A lot of people have preference and their reasoning behind it.
I have bronze guides in my ported J's, steel guides in my ported X's... they've both done fine. .528 , .575 lift ea.
No reason other than cost or preference.
The factory didnt use them, thats cost, but the motors went over 100k at least. So there ya go.