Hi Mozter,
I tend to agree with Cyrus on this issue, and both answers have already provided a great deal of insight.
But.. I'll throw my own two cents in as well, just in case you're still torn. There are Pros and Cons to each approach, as already mentioned. This dilemma most commonly arises when optimizing eCommerce based sites with multiple categories and subcategories, and a lot of times the best approach depends on the industry in question.
A little bit of keyword research is always important and will likely shed a lot of light on how users search for products in a particular niche. Google's Keyword Tool and SEOMoz's Keyword Difficulty Tool are both great resources.
Cyrus already noted several benefits of a shorter URL structure, and I'll expand on that as it relates to commerce driven platforms.
Like over-optimization, keyword cannibalization can be a major issue when optimizing products within the same category. For example, the URL you mentioned will likely have several similar URLs:
Mybrand.com/software/tablets/ipad/supertrader.html
Mybrand.com/software/tablets/ipad/product2.html
Mybrand.com/software/tablets/ipad/product3.html
and so on...
The result of this structure is that you have multiple URLs that are competing to rank for the same keywords (software, tablets, and ipad) and 9 times out of 10, all of the URLs will rank lower in Google, rather than a single URL ranking higher in the results.
If you were a potential customer, what would you search for? "SuperTrader Software for Ipad Tablet" or "SuperTrader for Ipad"? My guess would be the 2nd.
Assuming a more short-tail keyword search i.e. "Ipad Software", again you'll have multiple URLs containing those keywords, and likely a lower ranking for each.
Also remember, the shorter the URL, the more relevance that is placed on each keyword in that URL.
My suggestion is to use a flat structure that contains more descriptive keywords such as:
Mybrand.com/tablet-software/ (Category Page w/subcategories for each OS)
Mybrand.com/ipad-software/ (Category w/ software products for Ipad)
**Mybrand.com/supertrader-ipad/ **(Product - SuperTrader for iPad)
Mybrand.com/android-sofware/ (Category w/ software products for Android)
Mybrand.com/supertrader-android/ (Product - SuperTrader for Android)
This should allow better optimization for long-tail and short-tail keywords and help to avoid multiple URLs competing for the same keywords. It will be much easier to process for the user as well.
Also "Apps" may be a better choice than "Software" but I'm sure the competition is much fiercer. 
Finally, on a side note, if you're using Magento as your CMS, I'd suggest removing the ".html" URL suffix from the URLs and Categories and replacing it with a trailing slash by going to System --> Configuration --> Catalog --> Search Engine Optimization. I'd be glad to help you with enabling the shorter URLs and Rel Canonical Meta Tags to best optimize this structure in Magento as well. If you're running another eCommerce Platform, I got nothin' for ya. 
Hope this helps and good luck.
Anthony