Arriving at Yak Kharka means reaching 4000 metres of altitude (which is already fairly exceptional) after walking for a week (also atypical for me) in one of the most beautiful mountain ranges in the world. Needless to say, it's a really great feeling!
The spot consists of 5 lodges or tea-houses where you can sleep and eat. There's not much else to say... if you still have a little energy left, it might be worthwhile to continue to Ledar (1 hour / 1 hour 30 min further) which offers more beautiful viewpoints. If that is not the case, it's not a big problem! I spent a good part of the afternoon playing cards in one of the lodges and had a pretty good time.
The trek around Annapurna is perhaps one of the most touristy of all Nepal, or even of the world. Many will tell you that the country offers plenty of alternative options that are much better because they are less well known. I have only done this one, so I can't really compare. This being said, it seemed great to me from all points of view (landscapes / trails / comfort / costs). So if you are planning to include it in your tour of Nepal, don't hesitate for a second!
I should add that I visited Nepal before the earthquake of 2015, so it is possible that the places have changed since then.