I've done a Haggis and Shamrocker trip and they were both fantastic. I did a Haggis trip at the begining of the year and enjoyed it so much that I decided to do a Shamrocker. I did the 3 day Haggis tour to Skye with a mate and it was great. A little quick as I have been told there is way more to Scotland that just Skye and Loch Ness but it covered the essentials and has made me want to see even more of Scotland.
I also did the 3 day tour in Ireland and loved that too. The great thing about these guys is that not only do the guides know loads about the history and culture but they are so funny too.
On both tours we stayed in dorms which were comfortable and cheap and all we had to do was pay for this each night - dead easy. The best thing for me was that it wasn't all inclusive and beacuse me and my mate were on such a tight budget we spent our money where we liked.
Most of the hostels had kitchens, so we would get together with some of our tour group and cook up some dinner which saved us some money for the all important pints of Guinness! I would def recommend them. I think you can get a discount if you travel on both haggis and Shamrocher, but I can't remember the exact details. Best to give them a call they're super friendly.
Oh and we stayed at smart city hostel in Edinburgh, very handy for the Haggis tour as it is just at the bottom of the road and even handier Kinlay something or other, I can't remember the exact name but it's where you start the tour in Dublin.
Hope this helps!