So, I've spent about three nights in Jordan and have spent maybe four weeks in Israel. I'd go with spending time in Jordan. Unless you are Christian/Jewish religious, I don't see a whole lot of interesting things to do in Israel. Jordan OTOH has plenty of interesting sights. Petra certainly at least two full days. Jerash is on my list. Wadi Rum. I'm sure Amman could take up several days. Taking it slow is always good. I hate the "It's Tuesday, it must be Belgium tours." You'll have a great time. Do it your way. Don't listen to others. But if you do go to Israel, make sure you get to Bethlehem on your own and visit the tourist information area and talk to some Palestinian Christians about their struggles. And don't pay too much attention to Jewish tour guides. (OK, I'm prejudiced.)
In all things travel, do what YOU want to do.