Is the JR East pass worth it?

Hi, We are a family of two adults and two children going to Nosawa so planning to catch the Shinkansen to Iiyama, then back to Tokyo after five days in the snow. We will then spend the remaining five days in Tokyo. We intended to get the JR East pass but have now been told it would be better to pay for the Shinkansen and subway separately. I am totally confused and would love some advice please?

Tokyo-Iiyama return is about 17,000yen (less than the pass AFAIK).

As for subway, you need to know Tokyo has at least 14 different companies running trains and JR is just one of them, and their passes do not work on the other lines. The subway (two companies) cover some of the city, while JR lines provide a good method for both central Tokyo and further afield. Your choice of railway will depend on start and end points and may involve more than one train company. For Tokyo get a prepaid transport card (SUICA or PASMO) and use that across the different trains.

Tokyo to Iiyama... google tells me it is 8830 one way reserved seats.

Return trup is just over the 17,000 niigata nagano pass costs.

Just need to decide with 3 other days you will use pass. Day trip to Kamakura etc.