Either way, having too many devices connected to the same (single) radio can make it hard for any traffic to get through. A brief overview on airtime is here: http://www.tomshardware.com/reviews/wi-fi-performance,2985-1... -- in your situation, a minimum of two access points would be a good idea.
If you're looking for just access points, then I'd recommend a 3-pack of Ubiquiti UAP-Pros, spaced out relatively evenly around your work environment: http://www.amazon.com/Ubiquiti-Networks-UniFi-Enterprise-Sys... -- configuring them requires free server software, but once they're up and running, the server software can be shut down and the devices can run independently.
I recommend these as a Ubiquiti enterprise certified person with a current deployment of 30 UAP-ACs, on my way up to about 80 devices in total. I have one auditorium room with about 200 seats that, so far, 3 access points seem to cover without trouble.
Meraki is easy to setup and manage, it does not use any controller on premise since the AP connect to Meraki Cloud. You can manage all your Meraki AP from single dashboard even if you have separate physical location. This including user management so you don't have to only rely on WPA2 for WiFi security
Regarding the AP itself, if budget allowed make sure the device support 802.11 AC, most new devices support this (CMIIW) this run on 5Ghz band which on most places less crowded than 2.4Ghz. Usually this kind of device support dual band with 2,4Ghz to also support
At the very least make sure the AP you will buy support dual band 5Ghz (802.11 N) and also 2.4Ghz (b/g/n).
Most dual band support feature like band steering (this might be ruckus term, but others should have similar feature). Basically the AP will offer the 5Ghz to any device want to connect to them first, if the device can't connect then they will offer 2.4Ghz band. Having people connected to 5Ghz band is improving the network performance that people get because less inteference in this band.
I've found older Apple Airport Extreme's work really well and are easy to setup and manage. I can't personally comment on the current version.
Ubiquiti APs (and routers, if you like, but they're way more limited)
Or Meraki, if you have lots of money.