extruded:
-melted base
-less durable overall, but when core shots occur, only that direct area that makes contact will rip out of base
-cheaper
-slower
-easier to color dye (invalid)
-holds less wax
-will be fantastic for rails and urban because base is so dense and holds up for wear and tear
-will find extruded on devoted park sticks
Sintered:
-compressed powder
-faster
-because of construction, bases will hold wax better because micro-holes in the base between powder in air pockets will allow wax to seep through and become worn off much less rapidly
-better for jumps because of speed
-core will "tear" and "peel" when core shots occur, making damage much greater
-pain in the ass to repair
-unless a hybrid base, will be less durable on rails in the long-run (mainly unnoticeable for under 3 years)
-easier to hand wax (if your iron is broken)
-dries out faster if wax is not present
- quality bases usually on competition-level/higher end skis
I personally enjoy my sintered bases more because I like jumps and speed, although even though I am in the east coast too, an extruded base (Line TC Crew ski might be a good choice) will be much more durable on rails and if you aren't looking for speed, then I would go with extruded. If not, then go with sintered.