The Turkish Tentative list is a bit of a mixed bag. You have sites like Kaunos, Zerzevan or Mor Gabriel that are clearly WHS material. And you have sites like Izmir, where you wonder what specifically they refer to. It feels like the Turkish authorities use the tentative list as a work in progress list and that each region is free to submit any site they like to submit. Interestingly, I found several sites that according to the official signs were "inscribed on the Unesco Tentative List". If there was such a thing...
The Ayvalik nomination feels more like a draft nomination. I made a few markers in town, where to go and what to visit, but it was hard to pinpoint OUV. Ayvalik certainly has its charm, though. An old town with cobble stones. A nice port area. Some olive factory buildings, nowadays parking lots or tourist olive hops. And old churches. On the other hand, the town could use some paint and less cars.
I stayed for a night in town as a stop between Troy and Pergamon. It's a standard bus stop for buses from Istanbul to Izmir. I am not sure I saw the right places, but it was a pleasant night.
OUV
I wouldn't see a reason why Spanish Olive farming would be superior to Turkish Olive farming. And Ayvalik had a certain hard to pinpoint charm about the old town. With some renovations in town and some polishing of the nomination file, who knows? But as is, I don't think it belongs on the list.
Getting There
If you travel along the Western coast by bus from Izmir to Troy, you will stop in Ayvalık. The bus station (otogar) is on the highway a few kilometres outside of the old town. There are also local buses to Bergama/Pergamon. I came from Troy in the evening and left for Pergamon in the morning the next day.
From the bus station, you can take a local bus or a cab. You can also walk but there is a hill between the bus station and the town proper. I stayed in a historic townhouse in the old town. The cabbie had problems finding the way in the narrow cobble stone streets. Eventually, I just walked and I would encourage you to do the same.
While You Are There
Nearby Pergamon is a must. And you can continue up the coast to Troy. The area also holds several tentative sites, both in Turkey as well as in nearby Greece (Lesvos). Supposedly, the best parts of Ayvalik is the island off the coast: Alibey Adası. The area also has several beaches.