I was planning to buy a house until my research concluded it's extremely difficult to sell pre-owned houses. Yes you can get an extendable lease on the land or set up a Thai company which has so many grey areas. Its just too vague right now.
I did read the government are considering extending leases to make property purchase more attractive. I think 99 years was floated but don't quote me on that.
Who wants to buy an old house when there are so many new ones being built everywhere? I wouldnt.
I'm totally against renting as it's dead money so I would look at a good condo or wait to see if laws change next year. Probably best to consult a lawyer