I’ve been using OS X Lion, the new Apple Mac operating system for a couple of days and I have relearned an important lesson about application design: when designing applications, more is often less.

Overall I have found the refinements in the OS X Lion user experience delightful. The new mission control, dashboard and trackpad swipe features are magic. Spotlight, the OS X search capability, seems fast and more accurate; I think full screen iPhoto is wonderful. I look forward to learning more about versions. In all of these areas of improvement, Apple has refined the user experience while leaving the core feature set basically the same: Spotlight is still a search utility, iPhoto hasn’t changed and the Spaces ability to utilize multiple virtual screens has been vastly simplified with the new swipe capabilities.

Unfortunately, in one area I believe they reached a bit too far, added too many features and made the user experience too complex. For the past couple of months I have been using the Sparrow email client. On the company’s web site at www.sparrowmailapp.com they state “Sparrow is a minimalist mail application designed to keep things simple and efficient.” I find Sparrow the fastest and most efficient way to manage my multiple email accounts on my MacBook Pro. With Sparrow’s “minimalist” approach there are times I wish for an additional feature, however since my productivity is so much greater with Sparrow I stick with it.

Then three days ago, after installing OS X Lion, I gave mail.app, the built-in OS X email client another try. Many of the “industry experts” raved about the enhancements to mail. Here is what I found: Mail.app is a feature-rich email environment with full support for threaded conversations, an iPad style user interface and improved search. While this is all very nice, Sparrow is still more effective for me. Let me explain.

I use multiple Gmail accounts and an Apple me.com account for my email. Mail.app maps each Gmail label to a folder. When I want to move an email from the inbox to a folder in mail.app the move command lists all of my folders for all of my accounts. While this is extremely powerful—allowing users to move a message from one account into any folder on any other account—I have a lot of folders, and for my purposes, rarely need to cross-file emails. The unintended side effect is that it is very hard to find the correct folder when the move command displays a list of all of my folders across all email accounts.

Sparrow on the other hand takes a different approach. First and possibly most important, it is more well-integrated with Gmail in that it understands that Gmail labels are not just folders. When I am reading a message, from the unified inbox, it gives me the option to either label a message, or label and archive a message. The labels presented are the labels local to the specific Gmail account. Sparrow’s approach is more limited than mail.app’s, but this is in fact exactly what I want to do 99 percent of the time. It makes the task of labeling and archiving an email much easier.

In a second example, Sparrow has a wonderful “quick reply” feature. When using quick reply instead of opening a new message window Sparrow scrolls the message down and presents a small entry panel at the top of the current message. This panel does not include address information or signatures, just a place to write a short reply. The feature makes a quick reply feel similar to replying to a text message. If you need access to headers and signatures with one click the quick reply opens into a traditional reply window.

It makes sense that Apple would want to improve their mail client or introduce one that is more dynamic and feature-rich. Simplicity and ease-of-use, however, is what attracts people to their products. If anything gets added to a product, it should be value; if anything gets removed, it should be complexity. At the end of the day, in this case as in many others, more is often less.