Actually, for clips, they keep 40%. Unless you meant the vendor gets to keep 60%, which is indeed the case. It's pretty painful. For physical videos like DVDs it's 25%, but even though it's a smaller percentage, one must take media and shipping expenses into account. Not to mention that the vendor does pretty much all the work with physical product orders, Videos4Sale.com's role being limited to handling the transaction and sending the order info to the vendor.
On the other hand, I don't have the infrastructure to run such a store on my own. While I do think the fees are a bit high (especially given the huge number of vendor-customers they have), at least C4S/V4S provide unlimited disk space and bandwidth use, an easy-to-use standard store design, and, most importantly in my opinion, a system for processing credit card payments.
The latter item is very significant for me, what with bank and credit card companies being very reluctant to do business having anything to do with adult stuff nowadays. It's a market that tends to involve more fraud. That's why PayPal closed my account without warning a few years ago (after all, god knows I deal in disgusting, depraved smut). There's also the advantage of C4S being a very popular and well-known site.
So anyway, even though I wish I could do it on my own, it is convenient, and frankly I don't really have much of a choice. As long as one accepts the fee, understanding that they get good service in exchange, I can recommend C4S to vendors.