The biggest problem with remotely hosted shopping carts IMO is the fact that you lose too much control.
A couple of for instances...
As Scottie mentioned, I'd have to be very sure before signing on the dotted line that the remotely hosted cart does
not force the use of either cookies or Session ID's. And I'd grill the folks who do have control of the code that it will never require those items, and have it written into the contract that if they make a change like that which keeps the spiders away that I have every right to cancel the contract with no penalty.
With a shopping cart you're hosting yourself, you can usually tweak it if need be to make it spiderable. Advantage Self-Hosted.
Then there is the ability to edit the layout so that it matches that of your main site. Most remotely hosted carts offer some customization, but not a lot. I don't want to raise any questions or doubts in my potential customers minds at that crucial "buying decision" moment. So I stay away from hosted solutions whenever possible. Advantage Self-Hosted.
Third, I like to have the option of tracking absolutely everything. Not only how a visitor finds me, but what page they landed on and what page(s) people exit the site from. I track all kinds of things, because you never know what little tidbit of information may help you to see a pattern. But if you can find a pattern in what non-buyers are doing you can often correct it and increase your conversion rate exponentially. Advantage Self-Hosted.
Last is the Cost factor. A Self-Hosted solution is normally going to cost more at start up, especially if you need to set up a merchant account to process the sales. But over the long haul, a remotely hosted solution will cost you much, much more. And changing from a Remotely Hosted solution to a Self-Hosted one is a royal pain in the arse.
(Running everything through your own Merchant Account gives you infinitely more ability control potential fraud and chargebacks too, but that's another discussion.)
From the Designer/SEO perspective, this one is a bit of the toss up depending upon the client, their budget and what sort of mindset they have. Personally, when I start a site I look at it as a Business and I
assume it is going to be at least moderately successful. So I don't mind paying a little bit more now, knowing I may not start realizing the savings for a year or two. Back in my design days I always urged clients to go the Self-Hosted route. But not all did.
Those who didn't take my advice, then saw their site become more successful than they ever dreamed it would because they didn't understand how effective Internet Marketing can be, have all whined to me about it eventually. It is not uncommon to see a 4 figure per month difference in the cost of Remote Hosted Carts and Self-Hosted Carts for a decently successful site selling items that run a couple hundred dollars. It's never smart to throw away that much pure profit.
The only thing they seem to whine about more than what they're losing every month is the cost to Fix it by switching to a Self-Hosted cart after the fact.
I have the same answer for both of those though... I told ya so!
<edit> Looks like I need to start typing faster! </edit>
Edited by Randy, 04 February 2004 - 10:05 AM.
This is one of those questions that feels like the answer should be obvious but I'm missing it. 
