Reddit mentions of SHOP FOX W1727 1 HP Dust Collector

Could anyone compare and contrast a dust collector vs shop vacuum.

Dust collectors are designed to move a high volume of air but don't have a lot of static lift. It's designed to move a lot of dust but don't do well if you 'clog' them. Where as with a shop vac have lower flow rates but have better static lift. (~90"H2O/6.6"Hg/7.5 kPa abs). With 406"H2O/29.92"Hg/0 kPa being the theoretical maximum.

Cincinnati Fan has a nice document that shows the different wheel types and then it loses me in tables I try to block out of my memory. I'm pretty sure both types of vacuums (well all vacuums cleaner) use a variation of the centrifugal blower.

A few questions:

1. What is the theoretical and real world max static lift that you can achieve with a centrifugal blower vs a positive displacement pump (which is what most vacuum pumps use).
   
   
2. What are the different parameters that determine what a centrifugal blowers specs are? Would there be a way to do something similar to a VNT turbo[gif] [html5] to change those specs?
   
   
3. Is there any type of positive displacement pump that has a similar performance/size to a centrifugal blower? You can hold a 1000 cfm centrifugal fan in your arms.
   
   
4. Some fans are 'ok' with being operated in a vacuum, some don't. For example if I 'stall' my fan (doing static vacuum tests). Is this more of a function of the motor? Lower air flow = no load = motor speeds up = it gets hot since it's an unregulated motor. Or do centrifugal pumps not like to be run in a vacuum? (Is there such thing as cavitation with air?). But if you designed the motor that could operate at the higher speeds with either better cooling or speed control.
   
   
5. How does whether it's blower or a sucker affect the design. For example a shop vac and dust vac vs a HVAC fan. Where one has to draw through the system vs the other what blows through it? HVAC blowers seem to have lots of small flat blades (Squirrel cage) vs a dust fan.
   
   5a) Does it affect the ducting? For example a 1000 cfm centrifugal fan needs a large intake or needs to operate as close atmospheric as possible. Where as as a blower it needs a bit of resistance from the system. Or does a centrifugal fan just always operate best in an 'open' atmosphere?
   
   ELIFE (Explain it like I'm a freshmen engin