My stay was very enjoyable and the staff was helpful.
I really liked the communal lobby area which was great to meet new people. I traveled by myself and I had someone to wander around town with every day. Additionally the communal kitchen was great for making meals if you're on a budget. Isaac's was close to grocery stores and several pubs so definitely worth checking out if you're in Dublin!
Dina's Hostel is definitely a great experience, friendly staff, nice common room to meet other travellers. I'd recommend booking in advance to make sure you get the type of room you want as it can fill up quickly but they will definitely do there best to accomodate you. The only reservation is that the internet doesn't quite reach back to all the rooms but this generally encourages more interaction with other travellers and is only and issue if you need to have a private Skype conversation.