If you differentiate between Marketing Qualified Leads (MQLs) and Sales Qualified Leads (SQLs), you're setting yourself up for failure.
In fact, even the use of Lead Scoring, in itself, can result in catastrophic sales failure for most companies. But the reason is probably not what you think.
The Rest of the Story...
It's widely understood that different marketing programs can produce leads of different "quality". But the issue that really matters is "time management," not lead quality.
The confusion arises from the fact that the attributes of a lead that make it worthwhile to a salesperson to pursue one day may be completely different from the attributes that make it worth pursuing on another day.
For example, if the salesperson is over quota and it's the beginning of the month, a lead with a weak underlying need may be perfectly fine to work on. But that same salesperson, if they need one more sale to make quota and it's the last week of the month, may only want leads that are ready to close.
Does your so-called lead management system allow for such flexibility? If not, get ready to fail.
Calling a lead an MQL to differentiate it from an SQL isn't dressing up a bad lead, it's covering up a bad Sales Management process.