It's great to have another credible browser for Android and Firefox 4 kinda works OK on my Xoom but there are two issues that make me hesitant to use it - Fonts - there is some "non-nativeness" there - they look blurry and - Heaviness - the native browser on the Xoom is just insanely light and fast (couple crashes everyday aside) but Firefox feels heavier to use. Part of that might be drawing, part may be slow startup and some just general UI element sizes.