Yep as usual. To be fair unless there is an accident it is not too bad travelling down, it's the returning home bit, the M5 is a traffic jam from Weston Super Mare to Taunton at the weekends northbound. The A303 is just not worth bothering with unless you are lucky.
Next weekend I am in Eastbourne for a wedding and as usual in the summer I will leave at about 8pm on Friday and drive through the night, it's the only way, in fact it's great.
I'm originally from mid Devon and a lot of the family are there so I go down fairly often. The 303 is my favoured route (having tried all the other options), but you have to be very careful with timing.........my Burgess Hill to Tiverton trips have varied from 2hr 30 (2am, alone, risking speeding tickets) to well over 6 hours (first Saturday of the school summer holidays). The real bottleneck is always at Countess Services going down.