Okay, first things first: I'm new here, so I hope I don't break any rules by advertising my playtest server here. So I'm making a map and I have my own playtest server on it. I've tried advertising on diffrent subreddits and steam forums, but the problem is that those communities are very inactive, so I'm gonna try posting it here. The map is in very early development and has been tested with a few players so far, but there's few players online at the same time etc. The server slots 32 players and is hosted in the UK. I also have a public steam group for feedback (https://steamcommunity.com/groups/FoxhillPlaytest). This is my first TF2 map and the first time I open to public playtesting, so keep in mind that I don't have several years of experience in this. Again, I hope it's okay to post this. Thanks. SERVER IP: 64.46.107.89:27015
TF2maps has a discord server in which you can add maps to the bot and playtest the maps, the Impromptu Map Tests pop up frequently and you can play some maps on the site with us. The tests are usually pretty active and it's really easy to add a map to the bot, you don't need a whole new server to playtest your map, come visit the discord!
There's nothing wrong with Foxhill having his own testing server more focused on his own maps. You might get more people if you use the TF2Maps servers, but using your own is perfectly adequate if you can get people on it.
I agree fully on spud's comment, of course that's only my own opinion, do whatever is easier for you.
Perfectly acceptable to post and use your own server, I've done it myself plenty in the past, but you will likely have an easier time getting a full server to test on using ours. We also have a handy feedback plugin that helps quite a bit. Just an offer!