You will find complains about every Entry level Cable/DSL.
To my estimate it comes from:
1. People trying to do things that the Router was not design to do.
2. People who don't know the issues that they are dealing with.
3. An "honest" bad production unit.
The main difference between the Entry level Cable/DSL Routers is the number, and the range of ports that can be open through the Hardware Firewall.
If you are a gamer, and or use applications that need ports opening, that is an issue you have to look at.
The link here includes info. About most Cable/DSL Routers.
Big List of Routers.
Take into consideration that most brands update every few month the Firmware, (thus upgrading ports capacity etc.) The best thing to do is to narrow the search to few Routers, and then look at the actual Data sheet of the Router logging to the manufacturer site.
Like TG, I use, and like the SMC Routers (I am not an on-line gamer).
Otherwise by the cheapest that you can get.