I'm a long term user of MS-DOS, Windows (since 3.0), and in the last year have bought a few s/h iMacs. Thing I've found most painful is how some items of software won't work on some versions of OSX. I think the 'no viruses' comments lead some to be complacent and it will all end in tears if they are hit one day, having been led up the garden path by the historic situation that virus writers have mostly targetted Windows. As you have both used Windows for a while, you are probably at far less risk using Windows on your family machine, and probably have lots of knowledge about software you've found useful without needing to start on a new learning curve about searching and testing software for Apple to do what you've been used to doing on Windows.
I have a couple of Intel-based iMacs (on which I can use Chrome browser) but it's not available for older PowerPC iMacs. I have some printer driver for MacOS v9 (one before OSX) and there was no new version once OSX came out...
Yes, screen looks fine on a Mac, though one has developed nasty lines down it, so I have used an adaptor cable and plug it into a VGA display, and another (hence low cost) only gives a blue screen (so has to be plugged into something else for colours!). I think I have 8 Apple Macs altogether, though the eMac (an all in one with a big CRT display) is still in the shed. 5 are of the all-in-one slim(ish) screen, one is the classic curved shape with CRT screen and another (G4?) is the model with screen on a rod from a hemisperical base.
I would never have paid full price for a new one unless I had won on Premium Bonds or it was on business expenses to provide for something work-related (and as I'm self employed, that's not going to be for a while).
I'd say that for the money you would spend on an Apple you could consider two good Windows systems and have fewer squabbles within the home when both DD need to do homework, or similarly when one is doing some homework and someone else (eg you or your DH, want to do something else). OpenOffice or LibreOffice (each one is Free) could be on one or both for MS Office compatibility.
OTOH, I have bought two iMacs in recent months on Ebay and both came with MS Excel and MS Word etc. Most I paid was around 200 including delivery, but obviously they're not the 'latest' models.
Running OSX v10.6.8 on two iMacs and 10.5.x, 10.4.x, 10.3.x on different other ones (someone here on MN was asking about upgradng from 10.6.8 just the other day, and then found a few others also using this version with no problems and few reasons to 'upgrade').