For dust collection, think CFM. What is the combined cfm of the two small shop vacs you are thinking about? I use a single ShopVac for all of the dust collection in my shop. This includes: table saw, band saw, miter saw, 13" planer, 6" jointer, oscillating spindle sander, mortising on the drill press, scroll saw, router table, and various sanders. I use 2 1/2", 1 1/2", and a 1" diameter hoses, depending on the application. The single vac handles all of these machines with ease. I use washable CleanStream pleated filters in the vac. When I was looking to purchase a new vac for the shop, I looked for one with the highest cfm I could find. The one I bought is an industrial rated unit and pulls 95 cfm. Yes, it was more expensive than your $30 vac, but it's nearly 20 years old and still going strong, and I will not likely need to purchase another one. The unit also features a tool triggered function, so you only have to turn on the tool that's plugged into it and it runs for 15 seconds after you turn the tool off to clear the hose. The single unit also takes up much less space in my 12'x22' shop. It works so well, I've foregone the idea of building a chip separator unit, relying on the 12 gallon tank capacity.
I've gone out to find myself. If I return before I get back, have me wait for me.
"Sawdust is Man Glitter"