It seems a bit dubious and highly dependent on what quality and quantity of games we're talking about. Humble Bundles are usually pretty good but then I only get around half of them for various reasons.
Firstly, I never get the uplay or origin bundles, and I'm not that big on steam; I like the drm-free style ones like the current one. Then, as I buy quite a lot of games myself, many times I already have too high a portion of a bundle for it to be worth getting. The subscription bonus of Legend of Grimrock 2 doesn't help sway me because I already have it, for example.
Ultimately, it's the fact of buying blind that worries me, and this subscription is a bit too high-priced, especially with the exchange rate for us Australians. It's more than ps+ or Gold.
I'll probably still give it a go however, I'm such a sucker. It'd better be damn good though! At least it's easy to cancel.
Oh, also, it really bothers me they've halved the cut to charity. It's simply not a good sign for their motives.