I have only mostly used a Wattyl Estapol Matt to finish my models and until my most recent model have had little to no problems with it.
The beauty of the Wattyl is that its just a trip to your local hardware store and cheaper overall.
This is one of my many models finished in Wattyl - the curves on the roof and corner posts as well as the sides give a bit of an idea on the finish you get.
The only problem I have really had was on my most recent model where I found the decal I used, reacted to both the Wattyl and also the Testors dull coat sprays - not sure if this was due to the sprays or the fact that the decal was only a few days old from printing.
This pic below ( I cant get it to show for some reason so click on it to reveal)
shows the effect with the first decal crackling. I had to do some gentle brushing with a Humbrol varnish to tidy it up to look as it does here below. Obviously this pic is seriously blown up in size so at a distance this one looks ok unless put under the microscope.
I eventually sealed the remainder of my decals with a light brush coat of humbrol satin and then an overall spray of Wattyl as shown here below. It was one long decal so perhaps the greater area also contributed to the initial problem.
I think the Wattyl does give a nice finish and of course is easy to use from the spray can. I know many of the guys in my local modeling group also use the Wattyl and it is recommended as good cheap option. Everything we do is either scratch built or produced from urethane kits we make, so we do have some experience with what we do. We are of course always learning and sometimes the products do change as well.
As has previously been mentioned though - a test done on a sample model never hurts if you can spare the time.