Big question here,
Some push only when they reach a score threshold, some push right a way when created in Marketo.
If you push right a way senario:
When you create a suspect in Marketo, sync to SFDC into a queue, when the raw suspects gets nurtured and more info is gathered you can then use SFDC assignment rules to auto-assign to a LDR based on business rules.
Set up all LDR reps views to show only MQLs, SALs. This way they dont see raw suspects in SFDC when they get synced.
Now the lead is assign to a lead owner in SFDC, until a score threshold is met then change lead status to MQL, now they pop up on the LDR view in SFDC. You can also add a SFDC Task to the lead owner with alert email.