Well, low dose pills tend not to be as good at controlling periods, there tends to be a higher incidence of spotting and irregularity. However, I have been talking ortho-lo for a year now and have had few problems.
I missed a pill once and it made me spot a lot, however. You have to be very careful to take your pill on time every day or spotting can and will occur.
As for the side effects, lo-dose pills are excellent for getting rid of bad side effects of birth control. I was very depressed while on orthotricyclen, but since I switched to ortho-lo I have had no problems. Switching to a lower dose could very well help with your blood pressure problems.
As a side note, ortho evra is known for its bad side effects. Switching to a low-dose pill would most likely help those side effects.
Hope this helps.