I personally like Dualtabs from Twinlab. For several reasons:
1. they are time release....you take one in the AM and one in the PM
2. they provide 100% of many items and much more of others, including the B complex
3. they have absorption aids....and ask someone that cleans portables toliets what they flush out....it will be all the normal stuff that doesn't disolve or absorb in your body
4. since taking these things about six years ago I have not experienced a cold or the flu
I get mine (200 count) for $22.95 plus shipping from:
https://www.webvitamins.com/ they have great service
I first started on these when I was trying to find quality for all the different vitamins I was taking. A very knowledgable individual told me about these. I've been happy ever since.