Last week, my esteemed co-blogger, OWC Michael, posted his findings on the new MacBook Pros. While I agree with him that they’re pretty nice machines, I do take exception to the assertion that removal of the ExpressCard/34 slot from the 15” MacBook Pro isn’t that much of a loss.

The main thing we lose is versatility. That expandability was what many people (myself included) saw as the main delimiter between the “consumer” and the “pro” lines – not the materials or the size. The Mac Pro has expansion options via PCI Express cards, and the MacBook Pros had the ExpressCard/34 slot. The iMac, the Mac mini, and the MacBook don’t have these options.

With the notebook replacing the desktop machine as many users’ primary computer, this expandability is a key option to many Power Users. The simplest example is for those who use an ExpressCard for wireless connectivity. Most of the major cell phone companies I checked offer an option to connect to their wireless data networks via an ExpressCard, yet none offered one in an SD format. This is a major snag for those who do a lot of traveling and can’t rely on an available WiFi hotspot for communication.

Then, there is also the versatility in storage. As I mentioned before, there are a lot of people who use their notebooks as a desktop replacement. With this use often comes the need (or at least desire) for faster data connection. While FireWire 800 is a nice, fast option, sometimes you need something a little faster – like eSATA. There are a number of eSATA ExpressCards available for fast connection, several of which also support multiple drives.

If FireWire 800 is fast enough enough for you (and, admittedly, for many it is), there’s still only one port on the MacBook Pro. What happens if you have more than one FireWire device you’d like to use at one time? Sure, you can daisy-chain the devices together, but if there’s a single FW400 device in that chain, it reduces all the devices on that chain to FireWire 400 speeds. A simple FireWire ExpressCard allows you to connect multiple FireWire devices without any worry over loss of speed.

Technically, if you have one of the new MacBook Pros and need an ExpressCard/34 slot, you can use a USB to ExpressCard adapter. However, the down side to this is that, rather than the 2.5Gb/s maximum transfer rate of a native ExpressCard/34 interface, you’re limited USB 2.0’s theoretical maximum of 480Mb/s – and we all know that USB speeds usually test considerably slower than that in OS X.

So what about that SD card slot we got in exchange? It’s “okay,” if all your devices use SD cards. However, what about users with cameras or other devices that use Compact Flash (like my Canon EOS Rebel Ti), Sony’s “Memory Stick”, or any of a myriad of other cards? They still need an external USB adapter, making that SD card slot all but useless until you shell out more cash for a new camera/phone/gadget.

I can hear a lot of you saying, “If the ExpressCard/34 slot is so important, then why not just go with the 17” MacBook Pro?”

The answer to this is twofold – price and portability. The 17” MacBook Pro is about $200 more expensive than its 15” counterpart. While that’s not too much more (less than 8%), the “portability” factor also comes into play.

While the extra screen real estate is nice, it comes at the expense of portability. It becomes a tight fit in many laptop bags (often not fitting at all) and on an airplane (especially if you’re flying “coach”), you’ll be lucky if you can open the screen all the way. This is much less the case with the 15” model. Trading that convenience for a ExpressCard/34 slot is counterproductive to the whole point behind having a “pro” notebook in the first place – portability with expandability.

In conclusion, while I’m rather excited about many of the features of the new MacBook Pros, the loss of the ExpressCard/34 slot has me looking in the “Refurb” section of the Apple Store until this oversight is corrected.