My advice would be to look into your local turning club before you spend any money. Visit a couple of their meetings and talk to other turners. You'll learn a lot. Check here
for a list of clubs.
Personally I would avoid anything from Harbor Freight. No offense or disrespect intended to those who own them but they were not designed by woodturners and it shows. Underpowered motors, odd (even unsafe) speed ranges, poor castings, and non-standard components are just a few things to consider. Many Grizzly lathe models also suffer from these ailments.
Safety is always my first concern. Far too many "budget" lathes have too high of a minimum speed for safely turning larger objects such as bowls. Ideally you want something in the 500 RPM range or lower.
Upgradeability would be the next consideration on my list. Look for a lathe that uses standard component sizes so you won't have to replace accessories if or when you upgrade to a full-size lathe. For example, MT#2 is the "standard" taper size on most lathes. 1"x8TPI is the most common spindle thread size on mini- and mid-range lathes.
I do fully agree with starting on a mini. They're a great entry point into turning for minimal investment. You mentioned that if one of you like turning you would probably upgrade later. More than likely this upgrade will involve going from a mini lathe to a full-size lathe. You'll probably still want to keep the mini as has been suggested. They're that good.
A few nice mini lathes to use as your "yardstick" in measuring others:
1) Jet 1220 - One of the best-in-class (IMO) but pricey.
2) Rikon 70-100 - Well built and a very good value in a non-VS lathe.
3) Rikon 70-200EVS - New model, EVS, looks good but no track record yet.
4) Jet 1014 - Comes in both VS and non-VS. Smaller capacity than its big brother but still a great little lathe.
5) Delta 46-460 - Newer model, short track record but getting great reviews. Pricey but still a lot of mini lathe for the money.
for an extensive list of new lathes. Hopefully it will give you something to chew on.
Sorry so long-winded. Hope that helps!