I'll leave router advice to others with the experience, but I'll offer one option/suggestion.
For reference I am on Bell Fibe(r) and have a 25 down, 10 up plan. I reliably get better than 25 down whenever I do speed tests. However I still occasionally get buffering issues or noticeable video compression artifacts when streaming.
The suggestion - Using PS3 you can still download movies from PS Store in full blu-ray quality to the HDD of the PS3. PS4 will not let you do this unfortunately. So, well before we watch, I download the full file to ensure full HD quality. This reason alone is enough for me to keep my PS3 around, even though Santa brought a PS4 last Christmas!
Your ISP connection is only part of the equation, the servers serving out the data stream may also slow things down and cause less than ideal quality.
