Good: the map display is nice; having a complete Romaji option is nice. (Compare Google Maps, which shows a lot of Kanji, even when you are supposedly reading in English mode.)
Bad: SLOOOOW! Long delay to load whenever you zoom in or out, or move the map. (Are the servers in Japan? Would it be faster if I were using it from Japan instead of the US? I guess Ill find out next month.) No legend — you have to guess what some of the symbols mean. No search by name means search is almost useless — you have to know the prefecture / district of a location to find it!
Neil Faiman about JAPAN MAP by itsumo NAVI