Some friends, relatively inexperienced divers, are tossing up Tulamben vs Candi Dasa. I'd be grateful for your opinions on the relative merits of these spots. Any recommendations for particular dive companies?
I recommend Tulamben instead Candi Dasa for inexperienced open water diver.
Tulamben dive sites are suitable for all level, generaly none to mild current (most of the time), shore dive / beach entry (can be tricky during high surf) - cost per dive is much cheaper than boat dive.
So far we've stayed/dived with Liberty Dive resort (LDR), Puri Madha, Tulamben Wreck Diver, Joe dive, matahari, and mimpi. All are good but I highly recommend LDR due to low guide to diver ratio (1 to 2 or 1 : 1).