If location is important to you, then this apartment should go to the top of your list. It's on Thessaloniki's main thoroughfare. Really can't get any more central. This is a studio, so small when compared to an apartment with a separate bedroom, but I didn't have a need for a huge space, so it was perfect for me. Very stylish, and it had the best pillows I've yet to come across - I've been using Airbnb for about 5 years! Check-in and check-out was a breeze.
I'm a local, now living abroad, hence I can't comment on the host's provision of local tips as I didn't need them.
Definitely one to add to your list!
Note: if you're planning on using Chromecast, bear in mind that this is a group of managed apartments sharing the same wifi network with AP isolation turned on - good for security but bad if you want to watch a movie, so come prepared with an alternative :)