It really depends on where you will be located, there is not only the JR group, actually 7 completely independent private companies, but there are about 20 major private companies.

I really enjoyed the Kyushu Railway Company: https://www.jrkyushu.co.jp/english/train/index.html

Also Kintetsu has many supper trains around Osaka to Kyoto and Nagoya: https://www.kintetsu.co.jp/foreign/e...ress/type.html

Remember the JR PASS isn't really all that good a deal, great compared to Japanese paying full Japanese fares (which is obviously what they advertise!), but you can do so much better with regional passes. I saved $300 on a three week trip by ditching JR PASS. Travel on JR central via Shinkansen is problematic, since that is their cash cow, they don't offer any Shinkansen passes, but do offer a very cheap discount Shinkansen ticket to foreigners, about $60. If you are sightseeing in Tokyo, Kyoto, Osaka and so will have your JR Pass sitting idle for days, it's a steal.