The 2003 and newer Explorers are much improved for safety, and probably among the safest truck-based SUVs. The wider track, independent rear suspension, stability control (optional) and safety canopy side curtain airbags (optional) are all great improvements from earlier models. They have also received very good crash test scores.
I do not have much information on crash test ratings for a 1995 Saab sedan. Even so, a child in a properly used rear-facing carseat is going to be VERY safe in the back seat of most vehicles. Rear-facing child seats with a 5-point harness provide excellent safety by themselves, in both frontal and side impacts. Installed correctly, a child in a rear-facing seat may even survive crashes that other passengers would not.
I'd say either vehicle would be a very safe for your daughter, with very low risks overall. For other passengers, the new Explorer is probably a safer choice, especially if you have the optional Safety Canopy and Advancetrac stability control. Just a few years ago, I would have probably recommended most sedans over an outboard seating position in almost any SUV model.
As a side note, keep in mind that LATCH does not necessarily improve the safety of a child restraint, though it may make it easier to install. If a seatbelt installation results in a good fit, it is just as safe as LATCH.
Finally, Ford does allow center LATCH installation in some of its vehicles, using the inside anchors fro the end seats. Please double check your owner's manual to see if the center seat is a designated LATCH seating position.