It's not going to work well, but it can work.
Give each router/AP the same SSID and password. It will appear as "one" network.
HOWEVER (and it's a big HOWEVER), you will find that (as previously mentioned) clients will cling tenaciously to the last AP they connected to, even if there's another nearby that's pumping out a stronger signal and the one you're connected to is barely passing traffic.
If -- an only if -- the routers support manually setting minimum RSSI (signal strength) thresholds, you can set that and it will improve roaming. But when a client finally jumps to another AP (whether minRSSI is set or not), it will have to go through authentication and addressing (DHCP) all over again. This can result in significant dropouts while the client is reconnecting.
With an enterprise WiFi setup, not only can you set minimum RSSI, roaming from one AP to another doesn't require reauthentication or readdressing; the transition is quick enough that most applications won't experience a dropout.
I don't really care what platform you go with, but it needs to be something with a controller that handles the authentication. Standalone units, even of the same model, generally won't be able to share authentication information without a controller, resulting in a poorer roaming experience. Ubiquiti's UniFi system is popular because it represents a low cost to entry -- sometimes even lower than consumer grade equipment. However, some people don't consider them sufficiently robust, and customer support has been historically poor. My company has installed dozens (maybe hundreds) of UniFi access points, so I've got a fair amount of experience with them and not so much with others.