Definitely, call the service centers and ask what an overhaul costs for which ever pieces you are considering. You can look up where your nearest service center is/contact info online. It makes far more sense to go directly to the source rather than hoping a sales associate has recently dealt with a service issue relating to one of the exact watches you have questions about servicing.
As for durability, I can't really tell you if Platinum is more durable than stainless steel. I'd probably treat my precious metal watches with a bit more care than my steel watches, although I'm pretty gentle with all of my watches. The question "Why get Platinum over Steel?" That's a bit like someone asking why purchase a pair of crocodile John Lobb shoes for several thousand dollars, if a pair of $250 shoes with croc embossing fit you comfortably. Sure 2 pairs of brown could look the same to most people so why bother spending more. There are things that go beyond simply the basic appearance and price. You get into the quality of materials, the workmanship, and intangibles like not having the same thing as a dozen other people at work, or appreciating the tanning process used with finer leathers.
I think Platinum is a bit of a thinking man's choice. It flies under the radar, it could be mistaken for steel or white gold by casual observers. Its not as blingy as yellow gold, particularly on a big watch like a Daytona. However, its a precious metal that is more durable than white gold, it needs no plating to look white (some white gold is rhodium plated because some compositions of WG in their natural state look dark gray), its has sort of a luxurious heaviness not experienced with steel. In addition, if you scratch gold, its very easy to polish the scratches out, but because its such a soft/delicate material you lose some of the metal (I've even seen 40 year old wedding bands that had nearly worn through in some places just from daily wear, it obviously depends on ones activities, but it can happen). However, when you polish platinum you lose almost no metal, you merely move the displaced molecules around, its just far more durable than gold.
Its purer than white gold, 95% pure platinum for most watches (I've seen jewelry grade platinum ranging from 90-99% pure, but the most common is 95%, again an 18Kt gold watch is only going to be 75% gold. In addition, one can consider the intangibles, its more difficult to work with than gold, its more difficult to mine ( I read something years ago to the effect of it take about 3 tons of gold ore to produce 1 ounce of pure fine gold while it takes 10 tons of platinum ore to produce 1 ounce of pure platinum). So you are talking about more work, more refining etc. In addition, companies usually produce far more watches in gold than they do platinum, so there is a rarity factor. Think of the number of gold Rolex watches one sees in person or even in a watch shop, relative to the number of platinum Rolex watches one sees. Platinum certainly not for everyone, and for some people maybe a steel watch is the right choice. If I were buying a precious metal watch and its going to be gold, I would choose rose gold, as its less brassy than yellow gold, and it looks like gold. I had a white gold watch, but its qualities didn't seem special enough to justify the premium over steel or even over RG or YG (WG, particularly if plated with rhodium often costs a bit more than rose or yg when a watch is new...and then you deal with possible re-plating issues), and it wasn't as unique or durable as platinum. However, IMHO based on the rarity, difficulty to mine, difficulty to work with, additional labor it requires to procure/produce, and its durability its worth a premium if one can afford a fine watch in platinum. I certainly hope to add a platinum watch in my collection some day. In the words of Ferris Bueller, ..."It is so choice. If you have the means I highly recommend picking one up!"
Thanks for the write up!