Aside from the syntax errors (corrected in one of the responses further down the linked thread) I can't think of what would work better. Is it that you're not comfortable with the level of php required to implement it? It's actually pretty straightforward, per the example implentation given:
<?
require("ups.php");
$rate = new Ups;
$rate->upsProduct("1DM"); // See upsProduct() function for codes
$rate->origin("08033", "US"); // Use ISO country codes!
$rate->dest("90210", "US"); // Use ISO country codes!
$rate->rate("RDP"); // See the rate() function for codes
$rate->container("CP"); // See the container() function for codes
$rate->weight("17");
$rate->rescom("RES"); // See the rescom() function for codes
$quote = $rate->getQuote();
echo $quote;
?>
You just need to swap in the relevant zip codes, weight and desired shipping type (all the parameter options are listed within the actual class). Feed them in from $_POST-ed values, or retrieved from stored values in your customer database. And feed the resulting rate into your cart application rather than just echoing it.
What specifically do you need that this isn't providing?
Aside - I did run a brief test on this and it does appear to be pulling accurate UPS rates. I'm pretty psyched to give it a try.
Now if there was only one for FedEx...