Repeaters, by the very nature of how they function tend to give 50% of the stated bandwidth, an AP - as it's connected via a wired connection - should give it's maximum speed depending on the server's ability to supply it or the WAN profile. Ubiquiti is the kind of commercial kit you'll find rolled out in large multi site deployments, it's proven to be capable business class hardware that's priced at a point that can make it a better choice in terms of ongoing support, stability and value than consumer hardware which often feels like abandonware (Asus being a great example), it has decent management options/interface and fits nicely with the enthusiast/prosumer market.
My personal thought process was as follows:
BT FTTC - they include 52/10 for less than the rest of the market offers 40/10 for after cash back/offers.
Modem HG612 - i'm on a Huawei cab, so I matched to what was being used, ECI works pretty much as well but as I had both I went with what worked best.
Asus AC56U - it's running 3rd party firmware, ARM based router with the same CPU/RAM as the AC68U but slower wifi and no beam forming. Neither of those are relevant to me so paying the extra would be a waste of time.
Ubiquiti Unifi AP's - I use wifi as a convenience, I don't want complaints about coverage or drop out, but the usage in the household is mobile devices, the AP is more than capable of saturating my WAN profile and handles 20-30 household devices with ease (family of four with phone/tablet/laptop etc. each, streaming device in each bedroom etc). I could have gone for the LR or faster AC versions, but speed is not a priority for me, the basic AP runs 2.4Ghz which is better for coverage and one AP covers the house, front and rear garden/drive and if i'm honest quite far away from the house.
This set-up isn't for everyone, others may prefer to go with Mikrotik or whoever they like best, the Ubiquiti EdgeRouter is a decent option as it allows for a more centralised management/reporting set-up and a one box takes up one socket/less space, but is far less optimal, if you reboot your one box to upgrade the firmware/change settings, you risk DLM, I can do that and still maintain sync, in the same way I can swap over to a Mikrotik to play with hardware VPN acceleration and my wifi will still work without having to go round each device and re-set it. Some people suggest wives and significant others complain about 'extra boxes', i've found they complain a lot more often if the wifi is poor and constantly drops out, so far no complaints.
