More broadly, they were designed for the hospitality industry for in-room coverage. Aruba and Ruckus both refer to theirs as “Hospitality APs” (and Ruckus also has one that has a built in DOCSIS modem for hotels that have coax but not data cabling to each room). So they’re designed not just for fill-in, but for covering small areas at low power and low density, and usually drop out a couple of Ethernet for things like TVs and VOIP - in the case of Aruba, those can be tunneled back to the controller or bridged to a local VLAN just like any switch port or SSID (they blur that line).
The Ubiquiti IW Pro/HD line were actually designed by the same team that designed the Ruckus ones - the entire team left Ruckus to go to Ubiquiti, (and later left Ubiquiti, so I don’t know if we’ll see a WiFi 6 in-wall from them).
Generally speaking, they have mostly hemispherical coverage with very little behind them - Ruckus has a metal mounting plate, as does ubiquiti, and in most commercial applications, you’ll find a large grounded electrical box behind the outlet, so they simply design them to not expect much signal off the back side. Aruba has a big metal heat sink on the back, so the same applies. Some (inlcuding the Aruba) will have a slight electrical uptilt to the antenna, because they’re designed to be mounted at box height - but if the pattern is hemispherical, then you can mount them on the ceiling if you wish. I’ve had to deal with thousands of them mounted on the wall up high because of installation practicality in the field, but it was on cruise ships, so the big metal box negates some of the coverage weirdness.
Here’s a snapshot of what’s available in this type of AP:
AP-93H (EOSL January 2020): 802.11g SISO, 4 10/100 ports,
AP-103H (EOSL April 2023): 802.11n 2x2, 2 10/100 access ports, 1 gigabit uplink port, 1 passthru port
AP-205H (EOSL April 2023): 802.11ac 2x2, 1 USB Port, 1 gigabit access port, 1 uplink port.
AP-303H: 802.11ac 2x2, 1 USB IoT Port, 3 gigabit access ports, 1 uplink port, 1 passthru port from back to front. one port can provide 802.3af PoE (when AP is powered locally or via 802.3at PoE). Integrated BLE.
AP-503H: 802.11ax 2x2, 1 USB IoT Port, 2 gigabit access ports,1 uplink port, no PoE. Integrated BLE/ZigBee)
AP-505H: 802.11ax 2x2, 1 USB IoT Port, 4 gigabit access ports, 1 uplink port, 2 802.3af PoE (when powered locally or 802.3bt) (Integrated BLE/ZigBee)
On all the Aruba APs, IPM will selectively disable power to various ports and features based on user configured priority and available input power. PoE ports are always e3/e4 for profile consistency across models
AP11D: Same hardware as the AP-303H, running InstantON firmware. Can also act as a router.
H510: 802.11ac 2x2, 4 gigabit access ports, 1 ethernet uplink, 1 USB IoT Port
H320: 802.11ac 2x2, 2 gigabit access ports, 1 ethernet uplink
C110: 802.11ac 2x2, 2 gigabit access ports, 1 DOCSIS 3.0 uplink
Ruckus also offers a “fiber backpack” for the H510 that is a SFP media converter/PoE injector that sits between the mounting plate and the AP.
UAP-IW (EOL): 802.11n SISO - 2 Access ports (one PoE), 1 uplink port. (this one actually sat mostly inside the box and was basically an active wall plate.
UAP-IW-PRO (EOL): Not much is known about this one… Had a few extra ethernet ports and maybe MIMO.
UAP-AC-IW-PRO: 802.11ac 3x3 - 2 access ports (poE Passthru),1 uplink port
UAP-IW-HD: 802.11ac 4x4 - 4 access ports, 1 PoE Passthru), 1 uplink port
MR30H: 802.11ac 2x2, 4 access ports, 1 uplink port, Integrated BLE.
9105AXW: 802.11ax 2x2, 1 uplink, 3 access (10.5W PoE budget), 1 passthru, 1 USB. This one was just released in Nov 2020.
AIR-AP-1810W: 802.11ac 2x2, 1 uplink, 3 access (1 PoE), 1 Passthru
AP150W: 802.11ac 3x3, 1 uplink, 4 access (12W PoE)
I know that the Aruba and Aerohive ones can act as a router and L2-L7 stateful firewall, don’t know about the rest of them.