There's some decent agents (I think they're decent anyway?!) who've done deals with them if you look on PublishersMarketplace, so not just the 'lesser' agents. 3 book deals too. Though they don't pay advances, you get a pretty good royalty rate plus dedicated marketing. I think compared to other houses that don't pay advances, they stand out as being a quality operation. You can always tell from the book covers - in my view, Entangled book covers still aren't as quality as those produced by the bigger houses but compared to some of the other dodgy Photoshop jobs by other non-advance-paying houses, they're good.
However, if any agent I'm lucky enough to secure got me a deal with a house that takes unagented submissions, I'd wonder what what agent had done to earn 15% or so of my earnings if I could've submitted my book myself? Sure, you get help negotiating contracts but a quality operation like Entangled aren't going to do you over. And if you're a member of an author society like the Society of Authors here in the UK, you get free help with contracts.
In fact, there's some agents out there that seem lovely and quite popular in Twittersphere etc, but when you look at their sales, they're all to houses that don't pay advances and take unagented submissions so you gotta wonder... how have they earned that 15% of my earnings if I could have done this all myself?
But beyond all this, I really like the look of Entangled. I just don't think you need an agent to secure a deal with them IF you've written something good enough for them and you're willing to sacrifice an advance.