There are as many answers to this as there are people who want to camp in a
van.  Everyone has their own opinion, and they all are right- for them.

My own feelings on the value of the Westy amenities are, in the order *I*
perceive them::

Pop-top- most valuable because it allows you to sleep without having to
rearrange your gear.  I'm only 5-11, though, and taller people don't care
for sleeping in the poptop.  Also allows you to stand while getting
dressed, cooking in the van, etc.  It is this particular innovation that
sets VW campers apart from most of the clunky high-roof campers based on US
vans.  I've always liked the straight-up poptops on some other conversion
types, particularly the one used by Country Homes.

Sink- having a source of clean running water all the time is worth quite a
bit to me.  I often camp in primitive sites where the presence of the sink
makes it a lot easier to keep clean.

Stove- Handy when it's too cold or rainy to cook outside.  Otherwise, I'd
just as soon cook on a picnic table with the portable stove that I always
carry.  I could easily live without the Westy stove and use a portable
stove inside when its cold.

Fridge- Too small and temperamental to count on as my only source of cold. 
I still use and enjoy it, but I always have a cooler as a supplemental
source of cold stuff and could go to a bigger cooler and forget the fridge
without feeling deprived.

A lot depends on the time of year you prefer to camp.  I enjoy the fall and
winter months and so the stove and sink are particularly useful when its
cold outside.  Then one can forget the fridge and just set your beer
outside.

I have added a heater to every camper I've owned and consider that more
important than the stove and fridge, because it extends my camping season
so much.

Many campers carry elaborate camping setups and have side tents, dining
canopies, etc.  Because I'm a lazy man at heart, I value the Westy because
all I have to do to set up camp is to pop up the top, swivel the passenger
seat, and fish the appropriate beverage out of the fridge.  But a camper
like the Multivan without the stove and fridge might suit me almost as well
as a full Westy.  

It is a fact that a lot of people are sure they want a Westy, buy it, take
one camping trip, and then never get around to using it again.  Personally,
I like this because I can then buy their campers!

My $0.02
Bill