I'm the author of the setting, so I'm a bit biased, but I think you're on the right track in looking at Morningstar.
I've been running a campaign there since 1992 or so, in some form or another, but in it's current state I'm running two, the first comprised of people with no advance info on the setting. The first started after the book was completed, and it's been moving along well. For the first five levels or so, I kept to info in the book, and all the PCs wanted to do was explore. Even so, after the first session, they had a handle on the flavor of the world, and had taken to it easily. To me that's a good sign. After they stopped being tourists
, they started to pull the threads I had layed out over our previous sessions, and the campaign started to take on epic proportions (in the literary sense) with big plotlines, and high adventure. If you want a larger than life campaign that isn't simply a technicolor rehash of what has gone before, I don't think you can go wrong with Morningstar.
As for starting there or bringing your campaign there, either could work. If you start there, here are a couple of *mere* suggestions, based on my experience:
Let the PCs tour for the first 5 levels, or simply start the PCs off at 5th level. Most important NPCS will be at least 5th level, simply because of the logic of the setting. Most citizens (Patricians) wil have served a tour in the military or otherwise earned their place, by the standards of the Brendirian culture (the one most fully described in the book). The PCs will start to get respect at about 5th level.
Use the revised artificer class. This can be found in the 'files' section of our [url=http://groups.yahoo.com/group/Morningstar_Apostles/
] Yahoo Group [/url]. After extensive play, it was found that this class needed a low level boost to be viable as a PC option, rather than predominantly filling NPC roles. Joining the group might also help for added material and ideas. if you join, be sure to post... It's been a bit quiet for now, but I check it often, so any questions you have will be answered quickly.
If you want to move your PCs to the setting, there are several ways. Thraxis, the world of Morningstar is a nexus of sorts. The reason it's so charged with magic is that it exists near a planar rift known as the Wheel, which draws magic and souls into itself, over the surface of the world. Players who travel in the planar neighborhood of this world might be drawn towards the Wheel, and find that their only escape is to Thraxis.
Another option I've toyed with was to have them subject to a summoning spell... they would be planar entities by Thraxian standards, and planar beigns are allowed to stay after being summoned. You might have to hook them to get them to overstay the summoning spell, but having something cool happening that they can't resist interfering with, like a battle between the Legions of Brendir and the barbaric Derudian clans. Imagine a pitched battle with (non-mechanical) scorpion golems, dragons and griffons on the Brendirian side, and undead beasts of land and air on the barbarian side. If they are truly heroic, you might put a small innocent village in the crossfire that they would want to protect.
Other ideas will surely come to you once you get the book, as well.
As for the feel of the setting, it has a dreamy feel that underlies a mythic power struggle. If bipedal capricorn mounts, humanoid aberrations who wear beatific masks, heroic eidolons in the tradition of Hercules or Rama, strange gods, and a living, adaptive prophecy are your thing, you've come to the right place.