If you like the way LW works, youll love Modo.
Initially I had some slight problems getting used to Modo, mainly due to the fact that some of the functions worked in a similar fashion to LW, but not identically. But once I got over that the rest was a breeze.
Some of the most important features are the not so glamorous ones. Like Bevel, its a cross between LWs bevel and Smooth Shift, all of their advantages in one, but not having their weaknesses. I still miss Vertibevel a little, but the important parts are incorporated directly into Modo, especially if you use the macros for repeating standard bevels.
Then there is the Construction Plane. It was a great day when Al Street produced his construction plane 3rd party plug-in for LW, but it always felt like you had to pause your workflow, set up the plane, work, then re-set the plane, Modo does it on the fly without breaking stride.
Edges. Those LWers that still hold onto the illusion that having edges incorporated just means that you can select two vertices at once, obviously have never used any application that had them incorporated. Its a whole new way of working.
It took Modo while to get Bend and Bridge, but it was well worth the short wait. Both work way better than their LW counterparts.
I purchased XSI and Modo just a few months apart, and to be honest I havent opened LW since the first week.