While there's nothing wrong with anything the synergy system uses; the pool needs some CYA and the borates are good; like Jason said, you really do have to keep an eye on your CYA. The higher the CYA is, the more chlorine you need in order to kill the algae, and bacteria, and stuff. And if you're running a CYA of, say 70, and a free chlorine level of, say 2, your water is not being sanitized properly; you have bacteria, and you're in danger of getting algae.
The reason why a lot of people in this forum use BBB is because it works, it's economical, and it is easy. I think most people here spend about $20.00 or less a month on chemicals. Liquid chlorine, either the 10 or 12 percent from the poolstore, or regular 6% from the grocery store, is sodium hypochlorite. It adds nothing to your water but salt. The "dry chlorine", either the puck or granular, add other stuff to your water. Cal-hypo adds calcium. Dichlor and trichlor both add stabilizer, or as it is also known, CYA. I myself run somewhat of a "modified bbb." I use 10 percent liquid chlorine most of the time, but I have occasionally used something different for chlorination. The calcium level in my water was low, so I use cal-hypo to shock. I wanted my CYA up a little, so I used trichlor for chlorination for a few weeks, testing my CYA a couple of times so I knew it wasn't getting high. And as far as BBB working, well, ask yourself, how hard can it be to pour bleach in a pool? Right, a couple of seconds. This site says 5 minutes a day to a sparkling pool, and that's what a lot of people who use BBB spend!
I also run my pump with my solar cover on. Only occasionally have had the skimmer get a hold of it, and then not so much as to hurt anything.
And I've never had a chlorine smell, red eyes, green hair, or burning or dry skin from my pool, either. As long as your pool stays in balance...