An article by Derek Singleton on the blog for Software Advice talks about five things that he sees makes SaaS unique, including the talent draw of cloud companies, the ability to scale up operations more smoothly, the way cloud software is being purchased and consumed and other reasons.

While Singleton makes a lot of sense - and I do like the folks on Software Advice and think they are generally smart guys - he is missing a few major drawbacks with SaaS that are holding things back for better enterprise adoption.

• It isn't easy to price your cloud consumption. Some cloud providers don't have pricing available until you sign up for their service. Others make it hard to figure out. Since everything in the cloud is priced separately, to the point where pricing pages such as AWS' here and Rackspace's here can get very complex to figure out what your monthly bills will be. This complexity has brought with it a new class of products that attempt to predict your consumption of cloud resources, such as UptIme Cloud and a new service called Cloud Cruiser. We need simpler pricing that can be understood by the purchaser before they sign up before the cloud can catch on.

• Scaling is all about better governance. Yes, it is nice that you can attach a couple or dozens of VMs when you need to scale up your operations, and you can do so at the click of a button or two. But that is missing the point. You need better governance tools to enable this quick provisioning. Just having a multi-tenant architecture or having a bunch of spare hard drives lurking around isn't enough. If you can't figure out in advance your policies for setting up the quick scale-up or scale-down, you are still limited by the warm bodies inside your data center who have to make these determinations. You might even need more ops people than before, or certainly different skill sets to handle these decisions.

• The cloud does need special client software sometimes. There are a lot of SaaS-based products that I look at that do require some specialized client code to be downloaded, or only work with particular browser versions, or both. Lots of management tools and VM security products require agents to sit on the hypervisor or the individual VMS. Quickbooks online, for example, requires an Active X control if you want to upload your desktop QBB files - and this control only works in some Internet Explorer versions to add insult to injury. The same can be said for remote access tools to get access to your cloud-based desktops: you need these to run a browser-based VPN or remote terminal session.