I use the quik chik. To me the grow gel is a waste of money. With proper attn and care the chicks will eat without the need for green dye. If they are getting the quik chik which is a vitamin drink they don't need the double overload with the additional nutriets they are now adding to the gro gel.
Gro gel used to be just a green dye for the food so they could see it better. with the added stuff they are putting in it now I feel we are getting too close to 'too much of a good thing'. Most chicks do very well with plain cool water and good starter feed from day 1 of arrival.
I have used both. My shipments that I didn't use Gro Gel with did considerably worse and had more health problems than the ones that I did use it with. I really thought it was worth the extra money, due to the fact my chicks were so much more vibrant and vigorous acting, I also had very few deaths.
I used both on 14 chicks I got at a local feed store. All 14 are now 4 weeks old and are doing great. Several years ago, before Gro-Gel was available, I used just Quik-Chick and also had very good results. I think they are worth the small amount of extra $$$ and I would recommend them.