Digital v Analog is mostly a matter of taste. I bought one of the new analog AEM widebands recently. Installing it is next on my to do list. The analogs are newer and have a light to indicate when the sensor is heating up (and therefore it isn't accurate yet) and there is another light for error codes. Both features are not on the digital version. Other than that there isn't a lot of difference other than looks. Here is AEM's page for the analog WBs:
AEM - Analog Wideband Air / Fuel Gauge
I personally like the analog better. The digital ones look like something from Knight Rider. The analog fits a bit better with the stock gauges which I like. You don't have an exact readout on the gauge like the digital but I wouldn't want to be trying too hard to keep track of it exactly when driving. I will just use the 0-5v output the gauge has and log exact values. All I want to know when driving is general trends and the analog will do that just fine.
FYI you can probably get the gauge cheaper elsewhere. I got my analog off of eBay for $207 + shipping a few months back right after the analogs hit the market. They've come down in price since release so it is easier to find a good deal. I think you can find analogs for $218 easily which is $10 less than ZZP and if you look hard maybe you can do better. Digital ones go for less than $200 all day on eBay.
