I wouldn't really recommend either of those. They both have 300mhz processors, which aren't especially powerful. Three bits of information that can help with recommendations are price range, connection speed, and why you want dd-wrt (vlans, VPN, dnsmasq,etc.).
Speed 3-4 mbps will fine for voip service
I have a principal router for my laptops
I'll be connecting this dd-wrt router to my principal router and connect the ata voip to it. The main reason is that I need to use voip over openvpn through this router
Price around 40-60$
TP-Link tl-wr1043nd v2 is about $45. It has a 720mhz processor that should be plenty powerful. It has 8mb flash, so the dd-wrt build will include openvpn.
E2500 cheap on eBay I wouldn't pay over $30.00 (US) for one... but they are solid boxes.
E1200v2 also cheap -- don't do a E1200v1 (only 4 MB flash)
If you don't need a lot of speed The E2500 or E1200v2 will do 6~7 Mbps with openVPN.. that's with one as server and another as client thru openVPN TAP. Shibby Tomato firmware works very well for this. You should get better if using thru an openVPN provider. Of course other VPN besides openVPN will also be faster.