Ty Gwyn at Mynt

Coastal site just outside Cardigan. Not been yet, but hope to

For
Views, views, views
beach
sunsets
beach kayaking

Against
Think its a long walk to the nearest pub/hotel

Llyn Gwnant - Snowdonia

Large activity based site in Snowdonia. No booking, but very large . Nearest town is Beddgelert

For:
great views
Campfires
At the foot of Snowdon
Pizza and beer onsite
Kayaking on site

Against:
can be windy as in the valley
No pub, but Youth hostel sells beer 1 mile away
Difficult on public transport