Nintendo were more leniant towards Rare compared to Microsoft, the delays on Rare's own games made them entirely better than if they bought them out on the original schedule date.
I hear all the time with what would Rare have produced on the GC and at what quality if they had remained at Nintendo?. Star Fox Adventures showed me that Rare were showing signs of age, it wasn't a brilliant title. Yes it was good, but it was lacking something. Probably because Ninty ordered Dinosaur Planet to involve Fox and crew.
I still think that Rare could have been great if they stayed with Nintendo, because they would have been given the chances that Microsoft didn't give them.
Looking at the XBox and 360 games Rare have produced, they do show signs of old Rare. But at the same time, show to me that they aren't the same, they are missing the magic. Grabbed by the Ghoulies is one such title which lacked everything that made Rare great.
But, they showed signs of improvement on the 360. Kameo, PD-Zero (ok, wasn't as good as people say it is, but it is playable). Then they produced Nuts and Bolts, and in my opinion it wasn't good. I havn't finished it, which is a first for me.
The game was basically a cart-based game, with the characters of Banjo Kazooie tacked onto it. Rare themselves said it was 70+% customisation/trolly-based and the rest of the % being platforming. I saw no platforming, well hardly any and it was all cart-based and customising. The missions were linier, they all felt the same and it got boring.
Probably why Microsoft put them on the Kinect developers list, they can't do much right these days.