I'm a home amateur - but I use sous vide fairly often - here are some observations which I hope answer your questions.
I have the Polyscience Pro Chef - same as you linked from WS. I find it accurate and reliable. I use the large open poly carbonate tub from Poly Sci instead of that big stockpot from WS. It's easier to work with but one caution: The pro chef model has a hard time keeping up to temp with a large/full water bath at the higher temp ranges..eg 85C or so typically used for fruit and veg. I fixed this by making a cover - since I bought mine Polyscience now makes a cover for the plastic tub. With a cover it has no problem maintaining even higher temps.
I experiemented with all sorts of foods in the beginning, but over time I found my favorite use of sous vide is parcooking proteins at a perfect temp for finishing later, and for eggs (you cold do a whole thread on the many different ways to do sous vide eggs!). The reason I bring this up is that, although I bought an expensive chamber sealer, I don't use that many marinades any more. I primarily seal meats with aromatics, and use whatever might have been the marinade in the final cook. Great examples are scallops or beef/veal tenderloin. Take beef...I vac seal just with salt/pepper thyme and sous vide at 59/60. It's evenly cooked throughout - then when you serve you can sear briefly on high heat with butter, thyme, shallots, garlic etc, and create a crust with the flavors in the pan. Long story short - I wouldn't make the ability to handle wet marinades the key factor in your vac sealer decision.
On the other hand - I do prefer a sealer with a stong vacuum, coupled with a thicker plastic bag - as compared to the Ruhlman technique. The reason is I want soft foods to hold their shape. Although it may seem counter-intuiitive a weak vacuum seems to 'suck' suck on the bag forever, and eventually deform your food. Think scallops - you want a nice round scallop, not one squeezed out of shape. The stronger sealer I have seems to draw the air out of the bag very quickly, and maintain the shape of the food despite a very stong vacuum. Just my two cents on the subject :rofl2: