The ones I have are their so called "extra fine" quality, quite a few colours actually. Here's the comparison between W&N Permanent Rose and Talens Extra Fine Rose both PV 19.
Now on the first sight they may appear very similiar, however this is a scan, and the difference is slightly more apparent in the real world.
The swatches were painted on Fabriano Artistico 100% cotton paper.
I had to use twice as much paint from Talens to have similiar intensity for this test. All of their paints are more watery, so esentially if you would hav ethe same 15 ml tubes for both there would be more ACTUAL paint in Winsor and Newton. However some may find their more fluid consistency better, however I like to have my paint nice thick and creamy for better coverage and as much water as I would like to myself. So being a quite nice looking rose on it's own it does not make as vivd mixes as its competitor, and that is something that a lot of people don't take into consideration...
Talens did change their website and I cannot find the info anymore, but I remmember that they have confirmed using tomato starch as opposed to gum arabic like WN.
Don't get me wrong Talen's gouache is a good deal especially in Europe and even more so here in Poland where I could buy all of their 45 colours in 16 ml jars for 75 $... And there are certain colours I'd safely buy like the ones based on Pthalos, as those are very strong pigments.
Overall their offer consist far less single pigment paints than those of W&N, Schmincke Horadam, Holbein, M Graham etc. So I'd shop wisely.
When I'lll be runing low on gouache I'll try to order some tubes from Holbein and Schmincke and review them here.
Below a few more examples done with W&N designers gouache.