When reading online reviews of internet services, you have to understand that there are many variables. For example, most internet connections have low upload caps and if your overall bandwidth connection is less than 10mb/s, if someone starts uploading huge files such as images (and most of those are large these days due to high megapixel cameras on smartphones), your connection can be brought to a standstill and give the impression that your internet connection is slow or horrible. You may understand this, but most people do not so they blame the internet provider.
DSL (including Uverse) will typically give you consistent speed and quality. With DSL, you are connected directly to a local central office or hub. Bandwidth is not shared until after you are connected to your upstream provider. However, DSL is more susceptible to line noise, especially the farther you are from the CO/Hub to which you connect.
Cable internet, while typically allowing faster burst speeds, will tend to be very sporadic with both speed and quality, because you are sharing bandwidth with your neighborhood. That was less of an issue years ago, but now with streaming, smart TV's, mobile devices, etc. a lot more people are using high-bandwidth services online and especially during prime time, you're more likely to have quality and latency issues on cable.
I only mention this information so you understand that when people are complaining about their internet provider, just because some say their service is horrible or others say it is awesome, it does not necessarily mean that will be your experience.
This is VERY important .. when the tech comes out to install it, ask him/her how far away you are from the CO/Hub/etc. you are connecting to. Typically, line quality will start to suffer once you hit 3,000 to 4,000 feet, so they will compensate by lowering the speed of your connection in order to maintain line quality. They will test it before lowering it though and it is quite possible to have a solid connection even beyond 4,000 feet without any speed loss. Depending on the quality of the physical phone lines/cables/fiber as well as the number of connections along the line to other nodes (homes, businesses, etc.), the maximum distance before quality loss may increase or decrease.
If you are 4,000 feet or less away from the CO/Hub, you will likely not have any network quality issues and your latency should be low. The exceptions to this are if you are in a small town, isolated area or you have a non-AT&T phone service that has contracted with AT&T to handle their internet service.
So, to answer your question, AT&T should be perfectly fine for gaming and definitely for web surfing and streaming. AT&T is a huge internet provider in the US and given how many people play online games, stream things like Youtube, Netflix, Amazon, etc., there would be a huge uproar if their service was not working well in any of those areas.
