I am looking for a mesh router recommendation. I have a single story house about 4-5k square feet of property. In the home it is about 15k square feet but i would like to get reliable wifi in the back yard. I have looked over the deco units 100 times over and just can't decide on which is best. We pay for 400mbps suddenlink internet. We are currently using a 7-8 year old router which slows down the more device we use at one time. Speed tests are laughable at this point. I have a brand new modem cable of 1 gig speeds. We are definitely on a budget and every dollar counts. We basically do streaming and have at one time maybe 6-8 devices going at one time. We have 2 smartphones 3 fire tv devices( which at the most would 2 going at one time), tablet, amazon echo and maybe running a computer for mostly web browsing. Streaming content is the most data intensive thing we do all day. I know wifi 6 is coming out but i would rather wait on that until the technology is perfected and more price friendly. 

Thanks for the help