I just installed 5 APs and the Omada software controller on a Raspberry Pi (rpi). This was actually a residential install. I chose tp-link EAPs on price and features/performance.
1. EAP225v3 and EAP245v3 were both on sale ($70 and $90 CAD, or less with additional discounts)

2. I already had the rpi model 2 not being used. I got it for free, so $0.

3. existing wifi was not suitable with more people home all the time and adding a wired repeater did not give suitable roaming or fix coverage issues enough

4. also installed wiring for some computers; before all were wifi; 100m/330' so far and at least that much still needed for the rest of the wiring I still have to do

The final setup will be 6 APs, but I cannot yet access the locations needed to wire AP 5 and 6. AP 5 is presently installed suboptimally. AP 6 is not yet installed.

Two are EAP225v3 and the rest are EAP245v3, all running the latest firmware of 2.7 and 2.4; 3.2.10 on the controller. All ceiling mounted (except AP5).

All are powered using the included POE injectors; managed (to get VLANs) POE switches are not cheap. No guest network or VLANs yet, but this will be a future change.

Cost of the 6 EAPs (2*225, 4*245) was $513 CAD including tax. 

I used a Macbook for the wireless survey and to tune power levels; most are running very low Tx power. This was easier than I expected. I used both the native wifi diagnostics and an app called NetSpot. The latter was nicer as it auto-updated. Set power to lowest level. Walk around, check RSSI and noise. Adjust Tx upwards until happy.

Observations:
1. Omada controller install on the rpi was quite easy. Lots of guides online to just follow, though some are not quite correct. I should find the one I used and link it here. It doesn't use much CPU with 5 APs and 20-30 clients.

2. I didn't care for the screws/anchors provided with the EAPs, so used my own.

3. Physical Install was rather easy. Run ethernet cable (the not so easy part), terminate ends with RJ45, plug in, mount EAP.

4. Running cable in an existing dwelling is never as easy as a new build. I used Cat6a as I could buy it for not much more than Cat6 or Cat5e. I don't need Cat6a, but the cost difference was minimal. I still have ~670 ft on my 1000 ft roll, but I expect to use most of that for the remaining runs I need to do (2 more EAPs and then wall outlets for computers and other hard wired devices).
5. Configuration was quite easy (disclaimer: I do have a networking background. Others may find this more challenging). I walked around with my macbook, and adjusted Tx power as needed on the fly. I basically set it to the minimum and then increased it as needed only enough.
6. Apple Mac's lack of 802.11v/k/r support is annoying, but that's a MacOS issue.
7. Where is the short (400ns) GI setting that exists in TP-Link consumer routers? Not sure I could use it, but would want to be able to try it to see if it is better or not.

8. I adjusted the load balance RSSI settings per AP and will likely tweak this and Tx power a bit more.
9. I could have been ok with less APs, but give the cheap cost, I decided a few more was worth it vs. the signal attenuation of 5G through multiple walls. The layout here would have required an absolute minimum of 3 APs and that would only have provided ok performance. I wanted great performance, so I splurged for 3 more.

10. My router's wifi (AC1750) is now disabled. The hard wired AC1900 wifi repeater I tried was sent back.

11. Given nothing here supports 802.11AX and the benefits of that vs. 802.11AC seem to be mostly for high density deployments, I didn't mind buying this now vs. waiting for AX APs to be on the market, especially since I expect the cost of them to be higher than what I paid.

12. I used the EAP225s in locations where devices will mostly just be 1x1 or 2x2. I used the EAP245s where I would have 3x3 devices.

13. I used 1,6,11 at 20Mhz for 2.4G as this will mostly just be used by a few IOT devices we have. For 5G, only 36 and 149 at 80MHz.

14. I The lack of DFS channels was annoying. I want my 80MHz, so I have only 2 I can use. This is probably my biggest annoyance, especially since it exists in the EU versions.

Overall, the install went well and wifi performance has drastically improved from before. The places where AP5 and AP6 should be installed are ok, but not yet great. Will have further observations on roaming in the near future.