I'd have to disagree with the claim that it's just like normal melee at higher speed. Especially with the Mounted feat chain, it can be VERY powerful.
First of all, consider all the ways to increase your damage on a charge:
Lance - Double damage
Spirited Charge - Triple Damage
Deadly Charge (Cavalier PrC, S&F) - Quantuple Damage
Rhino hide armour - Quintuple Damage
Critical hit - Septuple damage
Power Lunge - Double Str modifier
From a tactical standpoint, your options also increase radically.
Versus a single foe, you can simply charge back and forth, never coming closer than 10 feet and casually doing 4x damage. Your opponent had better have reach weapons if he wants to touch you, since you always end up 50' away at the end of your turn (Ride-By Attack).
By level 6-7, you can easily (non-buffed) deal up to 75-100 damage like this. That'll drop most stuff at that level, so add (Great) Cleave to the mix. You can charge a GROUP of creatures and splatter all of them in 1 round.
If your opponent is powerful at range, get in close (you can move up to 100' and still get in an attack). With a DC 10 Ride check, your mount can attack along with you! Its two hoof attacks are perfect for Tripping someone (Large, 18 Str, 4 legs). You're still 10 feet away at this point, attacking with your lance. If he is tripped, he doesn't get full attacks unless he doesn't mind his -4 on attack and AC.
If your opponent chooses to attack your mount, you can substitute its AC with a Ride check, putting it in the high 20s on average (if you complete the Cavalier PrC, this can negate attacks that would hit AC 40 quite easily). If your opponent attacks you, with a DC 15 Ride check, you can use your mount as half cover.
If your DM catches on quickly (like mine), your mount actually becomes one of the most high-priority targets on the battlefield
