I have a store also (different ID) and while I love the variation format, I use a mix of them along with single listings - for me, it really depends on what the variations are, as well as whether I can reasonably guarantee I can restock them consistently.
For a variation listing, I like to be able to have a good gallery photo that clearly shows the main details of the item, as well as what kind of variations are available (if the difference is visual), so if I can't do that in an image, I tend to use single listings. I also don't like that sold-out variations can't be removed, simply because I think the greyed out title and 'out of stock' note gives the impression that variation will be restocked, so if I'm not able to restock, I will also use single listings.
The other issue is if the variations will have more than two differences. I recently added an item that can vary in shape and size, and I've seen some variation listings where they put them all in there, and either make them all the same quantity but the prices change between each variation, or make them all the same price but the quantity for each variation changes, so I went with single listings where I can have different quantities and prices between each one, mostly to avoid people misunderstanding how many they get when they purchase one.
In saying all that, I do actually prefer variation listings if they're suited to the item. It's a good way to cut down on 'clutter' (i.e. number of listings - I have around 1000 different items available, but use less than 500 listings), and it makes it easier to showcase alternative options once people are viewing the listing. They have other advantages, in that the variation titles are searchable keywords (as long as the variation is in stock - which is why I tend not to use the same keywords for variations as I do in the main title), and when the listing is GTC (good til cancelled), it can make it much easier to build up a decent sales history, and therefore higher best match rankings.
