John, I have cruise control on my Volvo 850 TDi, manual gearbox. I wouldn't be without it - especially for long tows down to Spain and Portugal. I only use motorways if I have to and find that the driving is more relaxed and much easier with cruise control. Yes I do have to change gear on long or steep hills but it's no problem to click CC back on as soon as I've changed.
Also, when not towing, I use it to set my speed in areas with speed cameras so I don't go too fast by mistake - I reckon I've saved pounds on fines..!!