Welcome to Coffee Snobs Serpeant.
I used to be a previous owner of the Brevista BES870XL, so hopefully my answers will be some benefit to you.
1. By best value, I'm assuming your budget is around that mark? if so, that's probably the 'best' you can get with a machine and grinder. Also in the past there's been ebay sales/ promotions where the price have dropped dramatically down to potentially $600 or lower.
2. I'm 99% sure that the BES870XL is the same as the BES870.
3. If you can stretch it (you suggested for under $1000), a lelit combi from jetblacks is roughly $1100. Made in Italy, designed to last. Or you can opt for a dedicated grinder and machine for a bit more. There are pros and cons on having dedicated grinder and machine vs combination machines. For example when I had my 870xl, I upgraded my grinder to a macap m2m and found that I used up much more bench space than needed.
You'll also need to ask between your wife and yourself; who will be making the coffees at home? I'd recommend maybe taking a home barista course, and going from there to see the process of coffee making is enjoyed as well. It is not for everyone.