Whoever thought these tapes provided better colour than standard tapes is, I am afraid, deluding himself. You are recording a digital signal, so the data is either there or it's not - the picture quality remains identical. Nor does HDV put any more demands on the tape than DV - the data rate is exactly the same - all the extra the compression takes place in the camera. The benefit of these more expensive tapes is that quality control is higher and they may be less prone to drop-out and, possibly, less prone to mechanical wear if you play the tapes a lot. Whether it is paying the premium for this extra feeling of security is a personal decision.
There are, however, genuine reasons for not mixing brands. When DV first came out, some manufacturers used a oily lubricant on the tape, others a powdery lubricant. Both worked fine, but if you use both tapes in the camera, the oil and the powder mixed to make a gunge. Now I believe tapes have been reformulated and this no longer supposed to happen, but I would rather not take the risk.
I am a professional cameraman and I get through hundreds of tapes a year. Drop-out is a very rare occurrence these days. I use each tape only once (they are there for back-up as I use a Sony Z7 that also records on memory cards) and after having tried many very expensive tapes, I have gone back to regular Sony Premium.