Patrick from Price Intelligently here. We think about this stuff all...the...time.
Overall, it's fairly dependent on the product you're selling, but considering what you mentioned check out these links:
1. The Saddest SaaS Pricing Pages of the year: Goes through a lot of general information on setting up your SaaS pricing, particularly on throttling your value metric appropriately: http://blog.priceintelligently.com/blog/bid/192297/The-Sadde...
2. A Study of the Top 270 SaaS Pricing Pages: Go into a breakdown of pricing pages as well as a bit of a how to: http://go.priceintelligently.com/saas-pricing-blueprint
3. Developing Your Pricing Strategy: Ebook on developing your pricing strategy in general: http://www.priceintelligently.com/
To answer your questions though, it's a tradeoff on simplicity versus spurring upgrades. Companies like Wistia.com have a lot of success with giving it all away and charging strictly on the throttle, whereas companies like Uservoice.com need to utilize differentiation because of their value metric.
Feel free to send an email if you want to talk live about this: patrick[at]priceintelligently[dot]com