I use chlorine because with a previous tub, I discovered my wife reacted to Bromine.
I'm currently using the Smartchlor system simply because the dealer included a years supply with my hot tub purchase. It's not smart by any means but it does work and is easy to maintain with minimal time invested. It also is good if you have extended time away from home. The biggest drawback of Smartchlor is the cost. It's expensive. The non refillable cartridges are about $16 each, figure 1 a month for a 300 gal tub and about $30 for the mineral cartridge which is replaced every 3 months.
So, if you need fast, and easy and you can't monitor your levels daily, stick with the Smartchlor. You will pay for it (about $75 a quarter). If you have the time and the ability to stick with a daily routine, go with the much cheaper method of dichlor/bleach.