We grow Daphne mezereum (red & white forms), blagayana (an early flowering prostrate daphne) and laureola which isn't a very exciting plant.
If you buy 'in flower' then you are buying and planting now which may not be the best idea. Poossibly buy now to see the plant in flower but then keep it in its pot until autumn?

I think Mezereum can be tricky. I've failed with it too. My mother had a magnificent one which was happy with its roots in permanent shade and its head in permanent full light - don't know whether that might help.

I agree about D mezereum, they apparently 'resent root disturbance'. I usually lift seedlings once the leaves have dropped and before the flowers open. I have had one with roots in semi shade and it is over 20 yrs old now. it does have its head in more sun now.
I also have D bhoula and they seem happy in my alkaline soil in part shade and damp. I have others that are D. odora, named varieties but they are a bit leggy possibly in too much shade and D tangutica which flowers later in the spring. that is a dark green leafed cinnamon brown bark when young with a rich scent.
I agree with Bulba and would leave it in its pot for the summer and pot in mid autumn.

A couple of years ago, I visited RHS Wisley where there are at least 2 of what I believed to be plants of a Daphne bhoula variety. They were large and thriving in an open aspect in the car park in the wind and full sun. Daphne Odora is semi evergreen in my location and is the cheapest to buy and seems to thrive even with little attention. As far a Daphne mezereum is concerned, my local garden centre won't sell them as they suffer greatly from mildew.

Thanks everyone, helpful advice and info. :)

Some forms of D. bholua is not particularly hardy (in the bad winter of 2010/11, every supplier of 'Alba' lost their plants). I'd say that D. tangutica or D. x burkwoodii would be worth growing as I found them trouble-free. They should last about 10 years, then go into a slow teminal decline, but that's not unusual for daphnes.

Thanks Andrew :) I had alook at them and see they are both spring-flowering. They are pretty expensive too...so I might accept that I don’t grow Daphnes rather than risk losing them. i’m not confident at all after previous experience.

Daphnes are not especially tricky, but they don't like extremes. They don't like drying out (which is why they are difficult to grow successfully in pots), nor do they like being waterlogged. They are expensive because they are difficult to propagate, either by seed or by cuttings. In my experience, they seem to have a life of about ten years

Thanks Andrew. I think the winds here would be too drying for them.