Pro: + some good drumkits included + further drumkits available
Con: - creating own drumkits is very complicated - unflexible - out of time - replaced by MarkII - much too late
This was also one of my first VSTi's I bought in Spring 2000. Around this time it was probably the best VSTi drum module available, sample-based with velocity layers.
But time has changed, and now with competitors like DR-008, RmIII, Battery or Attack there is no longer a reason to buy the LM-4, except maybe for the good included Wizoo drumkits and to use other available LM-4 kits (free+commercial).
To create your own drumkits, you have to edit text files and pray that you made no mistake. There are free/shareware kit editors around, but I haven't found them usefull.
Since around Dec/2001 it's no longer available and replaced by the successor LM-4 MarkII which improved some things (but came in my opinion much too late).