I had an SRM-313 with my SR-404 which might not have been the best amp for them (minya who stopped posting on Headfi told me his KGSS improved the SR-404, but he liked the SRM313/SR-404 so who knows). But I really didn't like the upper midrange emphasis on them. And I didn't think they were very tonally accurate. Also the presentation was just front to back, no depth or layering to the sound. I can accept that though, not a big deal given their cost.
Which is why I'm not too enthusiastic about the 4070, but I'd certainly like to hear them. I wouldn't be going out of my way to hear them given how much I like the SR-007.