Erlang style - case vs function pattern matching

I've got to the stage where I've written quite a bit of Erlang code now, and I can see some style (bad or good) creeping into the way I've been writing it. This particular idiom I'd like some opinion on - is it better (more readable/faster/whatever) to convert case style statements to function pattern matching?

E.g.

Compare (a contrived example)

case {Size > 100000, Type} of
    {true, ets } ->
         %% Do something to convert to dets
         something;
    {false, dets} ->
         %% do something to convert to ets
         somethingelse;
    _ ->
         ignoreit
end;

with

...
maybeChangeStorage(Size, Type)
...

maybeChangeStorage(Size, ets) when Size > 10000 ->
   something;
maybeChangeStorage(Size, dets) when Size < 10000 ->
   somethingelse;
maybeChangeStorage(_,_) ->
   ignoreit.

I prefer the latter in most cases but I'd be interested in other opinion.