Mars suffers from the same problems as the Moon. There's nothing there of which we don't have plenty on Earth, plus it's a lot farther away.
The Mars colony idea would be a bit more attractive if there were some change of a sustainable life. Humans managed to live in almost every environment on this planet with the simplest technology, which is a testament to us. Go us. A low tech life is simply not possible on Mars. A trip to Mars with no return ticket would be like swimming out into the ocean, just to see how long you could tread water.
You need a fairly large population and occasional resupply of high tech parts until they can bring their industry up to the level needed to make everything they need to live.
Off the top of my head I can come up with one thing Mars has that Earth does not: Nearby moons suitable for elevators.
This makes space launches a walk in the park. While the Martian gravity well is nowhere near as deep as ours it's still a lot of Δv--and fuel use with increasing Δv is exponential.
Now, while current technology *COULD* construct an elevator on Mars it would be awfully thick in the middle and there would be the big headaches of the two Martian moons.
Instead, lets build two elevators, one on each moon.
The Phobos elevator is 5680km long. On the downswing it's just above the Martian atmosphere and traveling less than 1/2 km/sec. You don't need much of a rocket to jump up and catch the cable. The payload transfers, the rocket falls back and uses it's engine to land. You might even be able to build an airplane that can hop out of the atmosphere to do this.
On the upswing the payload is just shy of Earth injection orbit--you can get to Earth by expending very little fuel.
However, the real power comes from having two elevators. Unfortunately, I can't find any numbers on the one for Deimos but it certainly can throw things better than the Phobos one--and it's an almost zero-energy transfer between the two elevators.
Thus spacecraft can be launched *FAR* more cheaply from Mars than from Earth. Once there's enough infrastructure there to build them it should launch all deep space craft and it might even be cheaper (although slower) to launch Earth-orbiting satellites from Mars.
