I'd go with the Euro pass, make sure you buy it before you leave the country. I'm not sure you can buy them in Europe.
I like to think my Euro pass saved me time. You don't have to wait in any line ups to buy tickets. If you get caught in Europe during a holiday the trains can get pretty crazy!!
Just double check that none of the trains require you to book a seat. Many trains in Italy and I believe France require this.
Also overnight trains you'll need to book a seat. If you enjoy your sleep you may want to book a coachette. I just sat in the general seating area, you end up meeting way more people and if you're lucky you'll get a train party going on. You can drink on the trains
or atleast I did.