I used to run a WDS setup with DD-WRT on three Netgear WNR2000v2 (Broadcom hardware) N300 routers.
Then, I moved to Tomato on some E2500 (v1, I think) Cisco routers, using wireless bridge mode.
Now, I've got a single Asus RT-N12/D1 with Tomato MultiWAN, and an AC1200 access point with gigabit LAN, connected to my gigabit wired LAN. (My internet connection is less than 100Mbit.)
Getting the same model (and sub-model!) router, and flashing both the main and sub router with the SAME third-party firmware, basically eliminates the compatibility issues that could arise, from a mixed-router or mixed-firmware environment. (But still doesn't eliminate the possibility of bugs in the third-party firmware. There usually are a few.)