When we bought our 2003 Suncruiser we also looked at the Winnebago version, the Adventurer. 99% of the coach is identical but the Itasca had a few more features as standard that were options on the Winnebago. If you added in these options on the Winnebago, it got pretty close to the Itasca pricing.
Also, the Suncruiser had a more upscale interior than the Adventurer. However, the upscale was not a better "quality" interior, it was just a bit more "decorated". Naturally, decor ideas vary from one person to the next so "upscale" is highly subjective and you may prefer the Winnebago decor. Qualitywise, they're both the same.
What made the difference for us was the dealers. Our nearby Winnebago dealer was pretty much a joke while the Itasca dealer was a grade A dealer. Seeing as how the coaches were so very similar, the difference in dealerships made it a no brainer. I'd keep that in mind when you search because a dealer who can give you great service is worth their weight in gold.