Thanks for the review. This is actually very relevant to the discussion that comes up here every now and then: what's a decent place to stay at in Ueno. Ueno is potentially a very useful location for those with an overnight NRT layover, but it suffers from dearth of acceptable choices for someone who demands a full-service, high-end accommodation.

I've never stayed at this particular Mitsui Garden hotel. When I look at the website, it seems quite decent with modern-looking rooms and nice breakfast spread. There're several room types >20m2 (personally 20m2 is the room size cutoff, below which I'd get claustrophobic). I will say the hotel's current 3.8 score on Rakuten Travel is disconcerting. I generally avoid any place that's below 4. However, your review is certainly encouraging.