I just took a look at their website, which looks lovely. I liked most of their covers, too. I checked the sales ranking on Amazon UK of the first book I saw on their headline crawl (which one would think would be one of their big sellers) and it was almost 87,000, which isn't great by any means. On Amazon.com it was almost 1,500,000. That doesn't translate into more than a handful of sales on Amazon.com*. So, for the UK it probably has better sales than most self-publishing, but for the US it doesn't appear to.
Just some data points, not a judgment or recommendation, either way.
(*Amazon keeps their algorithms a dark secret, but we do know they score like golf: the lower, the better.)