Some factors I allways look at for Hut Tubs:

-Trenching needed
-If it has a deck how difficult will it be
-If the deck is being built will they work with me to leave a few boards loose or repair if I have to pull up a few boards.
-If the a GFI disconect came with the tub (rare)or I supply
-If something exsisting would cause a violation like exsisting Rec or lamps
-I never end up doing any exposed outside surface mount piping but if they customer does not like my price I give them that option
-The location of the disconect
-The customer - If they can accept the fact they need a disconect on the deck or a pipe comming out of the house (I allways tell them what it will look like first)
-The house is brick or wood
-If the basement is finished
-If the basement has drop cieling
-Space to work around the panel
-Space and size of panel
-The panel grounding system
-Type and cost of breaker needed
-If it needs more costly materials like a lot of ridgid or compression
-Weather (I charge more when the weather is extreme)
-If I have to pay any fees for the job
-Like you said length of run

I allways get the disconect that comes with the GFI breaker. That is how it is done around here and it is a little cheaper here that way too.

My prices run $850-$1250. Average run about 90'all in metal pipe except for a sealtite wip at the tub. My compediters prices are about the same to a bit cheaper. Once in a wile another company prices crazy cheep around $250. These are the ones that double tap the A/C disconect with 30' of seal tite across the yard. With the wrong breakers and wires. I would say my material is about $250. It allways takes 2 guys a day to do.

Every customer thinks it's like addind a receptical and should be about $100. Most think they are getting ripped off until it's done. Then they say they didn't realize the work needed.

The Disconect should be more than 5'and with-in sight (60'?).

Tom