I've been out twice with different groups of friends on Lough Gill with Sligo Kayak Tours. Both times the experience was very enjoyable and everyone in the group had a great time. The tour guides are brilliant both from an equipment & safety point of view, but also as guides who can give information about the lake and the surrounding area. They're very open to questions too so feel free to have a chat with them out on the lake.
The tea / coffee and biscuits on Beezie's Island is a really nice touch where you are also given time to explore the island.
The equipment is in great condition and it's the only place I've ever had a splash guard which is great for keeping you dry.
I had some conversations with Barry (the owner) over email and he was always a pleasure to deal with.
Would recommend tours with Sligo Kayak Tours for both locals and tourists. A great few hours of fun!