Originally Posted by
startpacking
Haven't been to the Snaefellnes Peninsula, so can't help with that.
Have been to the South Shore. Unfortunately, you don't say which place(s) the tour you are looking at will visit. The South Shore tour I'd taken was worthwhile. The tour visited some scenic sights near Vik (black sand beach, rock formations), waterfalls and glaciers (which you will see in the Golden Circle). It is a long day, just be prepared for that.
I'd used Reykjavik Excursions for my day tours and I was happy their service.
My partner and I will be in Iceland in mid-September for 10 days and plan on spending four days on the Snaefellnes Peninsula specifically in the town of Stykkishólmur. Apparently the peninsula is quite beautiful and a foodie destination. The Hotel Budir is reportedly one of the best places to eat in all of Iceland, with prices to match. As a place to stay Hotel Budir seems to get fairly middling ratings. We're staying at the highly rated (in Tripadvisor) B & B called Bænir & brauð. We plan on doing lots of hiking and exploring!
Can't say how this compares to the South Shore.