No, I did not get my visa for Syria at the consulate in Istanbul. I went to the border without one and crossed near the Turkish city of Kisli. It took 7 hours to get the Syrian visa at the border, but I eventually got through.
I was told by other travelers that only Americans need to wait this long, as other nationalities can get visas at the border in a half an hour. Ever since that skirmish on the Syrian/ Iraq border where American planes bombed a Syrian border crossing, American travelers now need to get permission from Damascus before a visa can be granted. This usually takes from 6 to 8 hours.
The official stand is that it is not possible for Americans to get visas at any consulate except for the one in Washington DC. I did not try in Istanbul, but I do know that it costs around $120 for a visa from a consulate whereas it costs $16 at the border.
This price for Americans has been confirmed by many different travelers. Though I do know that the prices follow a gradient scale depending on what country you are from. I met a traveler with an Australian passport in Aleppo who was charged $70 at the border for her visa.
I say that your chances of getting a visa on arrival to Syria are probably the same as getting one from a consulate. I met many travelers in the country and most of them – Americans included – obtained their visas at the border. I have not yet heard of anyone being denied.
I just recommend not trying to cross the border on Friday — the Muslim weekly holy day. I crossed on Jumu’ah and it presented a heightened degree of difficulty, as the border officials were not sure if anyone was going to be working in Damascus to reply to the faxed request for my visa. But it all worked out and I got into Syria at around 20:00.
My recommendation is to try to get the visa at the border rather than wasting time and money going to Istanbul. The official position is that the consulates outside of DC are not even suppose to grant visas to Americans, but I would keep this option open as a contingency plan.
Please post a comment here on how crossing into Syria goes for you.
More information on border crossing at, How to get travel visas
Original question about getting a Syrian visa at the border
Did you get a visa for Syria while is Istanbul? Wikitravel suggests that you can roll the dice and hope to get in at land border crossing but it is risky, am curious to know your experience.