Reasonable... of course you need to look at the quality of the material.. eg the quartz has diff grade too! and also the hinges and stuff...

NP. Just ask your supplier what's the brand of the quartz. Generally if they don't tell you then it is general china made one. Those I doubt they have specs provided.

The higher the % of quartz the harder the counter top but like I said the bonding resin is quite important. Mine I can put hot pot on top and still no problem. You don't want to risk those china made quartz with unknown specs. That said if you use it carefully even china quartz will last you a long time. Just don't select those white ones because cheaper brands white color can be easier to stain ... even for quartz due to poor bonding resin