Hiwatt cleans are nicer imo and it's tough to find nice clean Hiwatts for a decent price these days. You could pick up a serviceable 70s Marshall JMP head for around £500 easy if you keep your eyes peeled.
Only downside on Hiwatts is they need to be LOUD to sound at their best otherwise they tend to sound trebley (imo). Also, I don't like the tone with Celestions either - Fanes are where it's at for classic Hiwatt tone. I remember my DR103 rig with a Sound City 4x12 loaded with 50w purple-back Fanes - ahh!!!, those were the days.