As you are saying your daughter owned the Focus, and you are asking about the Focus 2, I am just inferring you do have AT&T. (I notice your statistics have the Titan listed, as well as a ton of international posts. Are you overseas?)
Here is the general rundown of AT&T devices based on Forum feedback and reviews in my opinion:
Of all the first Generation WP 7 devices (Samsung Focus, LG Quantum, HTC HD7S, and HTC Surround) I would not suggest any of them. Not because they weren't good phones. The Focus and Quantum were both very loved and dependable phones, and the 2 HTC devices had a good following. It's just the older processors at some point will get bogged. With the next upgrade coming (called 7.8) these devices may truly show their age. No reason to risk it when there are inexpensive options out there from the second generation.
Now then, as LAK611 said there is the important decision of it LTE means something to you. AT&T in my hometown, and for that matter Verizon, have yet to add LTE, and so far I have heard nothing about it coming. I will just group them by LTE or Non-LTE.
The Focus 2 seemed to be a very poor seller, so I would worry about support. I would not worry about the device. The reviews were good, the forum on here was complimentary, and there were very few bugs reported. You could most likely find a new one for your price range if you look hard enough. I can say if the AMOLED 4" screen is your style, it is worth the purchase.
HTC Titan 2 is the phone my Wife owns. There are bugs here- we have problems with WIFI connection, a few reception problems with her calls, and callers have problems hearing her. I can't recommend it.
Nokia 900- You will have to pay a little more for it, but Nokia is all over supporting it. It has a great screen, been given good updates, and will be able to handle everything you throw at it. Highly recommend it.
Focus S- My phone. I love it. It has been a gemstone, dependable device. The camera is nothing special, but you will not go wrong. No bugs to warn about. Highly recommend it.
Titan- We returned four of these before getting the Titan 2, all for different problems. Stay away from this device like it has leprosy.
Focus Flash: Know someone with one of these- it is a small screen joy. 3.7". Very dependable and enjoyable. You could get one of these very, very cheap if you look. She has enjoyed it greatly.
Overall- Samsung has made very dependable WP 7 devices and you could find them cheap. Nokia is king- they will support their WP 7's and they are loved devices, you may have to spend a little more for one. HTC Titan series has been a bust in my experience- I cannot recommend them.
Good luck!! Hope you give a WP 7 a try!! Let us know what you do!!