Pros:
1. Very close to Ueno metro station (1 min walk) and Ueno JR train station (5 mins walk) - both stations have enough connections that you could travel anywhere in Tokyo with ease.
2. Free drinks area in the afternoon and evening for coffee, tea, soda, ice bucket.
3. Buffet style breakfast - Japanese style only, mostly seafood and savoury, but some variety with breads and pastries for vegetarians. Some days the soup and rice/noodles dishes would be vegetarian but not daily. The variety is good enough for a short stay.
4. Helpful staff, speak conversational English, and helped with luggage delivery services.
Cons:
1. Small room - but this seems to be standard size for most Tokyo hotels at this price point.
2. Breakfast could be a bit difficult for vegetarians, particularly if you're staying for a long period.