Does anyone MFGR. decent quality vents for Bath Fans, Dryers, etc?
H Depot wants almost $30 for the lousiest quality things. Dosn't make sense to cuople a high quality "Panisonic" bath fan with a pc. of junk wall or roof vent. Seems like the lightest breeze would open the damper and blow right in.

Usually the fan manufacturer also offers ducts and wall or roof caps with backdraft dampers, so I would try there first. You might also look for a NuTone dealer (probably at an electrical supply house) and see if their components fit.

If your looking to vent a bath with something more then just a noisy fan that does not really move air, do what we do. We install inline duct fans. We use Fantec units. The same fans you see for radon removal in homes. You can find a supplier on the web. They are real quite, provide good suction for venting and do not cost a whole lot of cash.
Just be sure to properly insulate the ducts leaving and entering the fan within the attic space. Not doing so will lead to condensate forming during winter months in the ducts. Also install the fan so water if condensate does form drains out one end or another. Do not install sidesways as the condensate will not drain and can freeze causing the fan blade to stick and burn out motor when you need it.

Yeah - I can get high quality fans (I love panisonic) but it's the WALL & ROOF "Caps" that are so crappy! And you can't tell by looking at them online. I installed a $5 Lowes wall cap that I'm happy with because its all plastic & seemed to seal well. I'd like a good PLASTIC roof cap because metal ones turn to rust in 5 years and who knows if the damper is rusted shut!

Purchase aluminum roof caps if you are worried about rust. Stay away from soffit vent system as the condensate can form and back up under the eve causing ice and mold issues on the overhang. Side wall vent if at all is best. No holes on roof to leak. No soffit moisture issues to worry about. Vent damper can be installed inside out of the weather so no worry there either. Just be sure to use a grill type vent hood so birds do not build a nest.