eCart 5 vs eCart 4

i would like to know the new technical feature (not design feature) for eCart 5:

this info i take from WA website:
* Revamped checkout wizard interface to help simplify the set up process - Enhanced!
* Full support for PayPal Canada - New!
* Database Presets - New!
o Added database presets for orders and order details
o Quick set up and configuration
o No database knowledge required
* Build Shopping Cart Without Payment Provider
o Allow customers to shop and simply provide a quote
o Let your customers submit custom orders and not require payment upfront
o Perfect for payment processing over the phone
* Separated server behaviors from buttons, allowing you to apply Add to Cart, Clear cart, Continue Shopping, Update Cart and Checkout functionality, without a button to be used for the trigger.

Any new technical features ?

Not sure what you're getting at. Seems like you just listed them. What's your idea of "technical features"?

in short: Unlisted feature

i would like to know in technical aspect if eCart 5 worth the upgrade ? it cost almost $90 for the upgrade... and i don't really see a major function listed in programming terms.. it only add a lot of design features

The way I look at tools is how much time and effort will they save in respect to their cost. If you need to do the things that are listed as new or improved, it's pretty easy to make that determination.

If the goal is to create an e-commerce site that looks and works the way you want more quickly, I wouldn't dismiss a tool that speeds up that process regardless of whether it does it with CSS, PHP, or server behaviors.

This is a pretty complete list of features. There are no more in this release. There are some design features, and some usability improvements, and some database management features... but those things are all included in your list.