Overall, that's not a bad price for removal, if its by a competent professional. There are guys out there who will take down trees a lot cheaper, but they're also the sort to do crazy and dangerous stuff, drop one through the house, etc. Buy once, cry once.
I can't see a ton from the photos, but what little I did see, it appears the trees are in overall good health. I personally wouldn't recommend removal unless there was something wrong with them. Even if the shade doesn't help the house, trees on the property add a lot to its value. Depending on location, it can add as much as 25%.
I'm a certified arborist, but I only do consulting. (I don't have a dog in the fight/dollar in the pot if someone wants to cut down or keep their trees) If it were me doing the assessment, I'd recommend keeping an eye on the trees, looking for any signs of decay or disease, and pruning out dead/dying branches on an as needed basis. I err on the side of the tree when doing consulting, and don't recommend a removal unless that's whats best for the homeowner and the tree.
Biggest issues I see affecting oak trees are typically hypoxylon canker (big smooth gray patches on the trees bark that gradually turn black in the summer. Its deadly and contagious, any tree with it needs to be removed.) Root rot (look for mushrooms and fungal fruiting bodies growing on the roots) And stress from soil compaction. (don't park your car under a tree) Most other issues I run into are from people trenching, digging, etc too close. Oak trees live a long time, but they will die from old age too, just like anything else.
A lot of mills are funny about taking yard trees. Never know if there will be metal, wire, nails, etc inside the log. A lot of the time though, you can find a small, portable sawmill company that will cut them, with the stipulation you replace any blades that your trees break.