The best used piano money that you can spend is that spent for a prepurchase inspection by an experienced tech who has no affiliation with the seller. You can probably locate techs thru your local Yellow Pages and interview them re their experience and comfort level doing this kind of evaluation.
The action work is a plus, the condition of the soundboard is a concern. Wide swings in humidity cause 'boards to expand and contract. Over time that process leads to degredation of the 'board's fibres. A good tech will be able to help you assess how well the 'board resonates. When 'boards are deteriorating, sustain shortens. You might want to check the sustain in the fifth and sixth octaves and compare the result to that of a new piano.
Listening to the demo thru cheap headphones, the treble sounds a little "tinkly." This could indicate deterioration or could be just the character of this piano - or could be just these 'phones.
As always when making a buying decision, it's tone, touch, appearance, then price that's within budget. When buying a restored piano, you're essentially paying for the restoration. This piano has little name recognition, so you'd want to buy it with the intention of keeping it.
As Phlebas posted, you can get lots of help on the Piano forum.