Marlin is good and you can't go wrong with his stuff.

The difference between Marlin and Alcan is that Marlin and most others build a "one size fits all" spring. In other words, they basically build one type of spring and how it performs is going to vary a good bit between a stock weight truck and one that is a fully loaded light duty expedition type rig, like mine, or 4Crawler, for example.

Alcan custom builds springs to your exact specification, including weight, type of driving and type of off roading.
They ask you a long list of questions and you have to visit a scale, before they build your springs, unless you just opt for a generic specification. But they are spendy too. They're a good alternative when you have a really unique rig or requirements, especially wieght requirements.

If your rig is not super overloaded, I don't think you could go wrong with a set of Marlin springs, although I wish he sold 3" springs instead of just 4 and 5 inch lifts.

ARB's OME 2" lift would be something to consider if you decided to just go with 33s.