One of the huge issues with 802.11ac is that it wants to use 4 channels and there are only 2 blocks of 4 in most countries...some only have 1.
In a environment with lots of neighbors it means everyone stomps on top of each other and nobody get good results.
Even though it will cut your top speedy you may be better off going to a single 20mhz channel and hope you can pick one that has less competition. If you are using 2.4g there is only 60mhz total bandwidth. You want to avoid 2.4g if you can get 5g to work. Many people are trying to run 40mhz channels in the 2.4g band which means they too are stomping all over each other and with only 3 20mhz blocks to choose from you tend to not get any without huge numbers of neighbors on...