I've taken this supplement for 2 cycles: each cycle consisting of 4 tubs (15 weeks each). First off, tastes amazing - looked forward to taking every day... Artic Lemon especially - tastes like lemon meringue pie... :) Didn't mind sipping through it while I worked out.
I've been training over 15 years so I didn't anything too much from it. Slightly increased my strength but nothing dramatic (based on my years of gym experience). It did increase my weight by around 10 pounds after a month. No this was not new muscle, but just the water being retained inside the muscle cells.
Compared to the new Maximum Performance stuff (which has Isolate peptides and costs a lot more), I just added 10-15 grams of Leucine powder to my shaker bottle when taking. In my opinion this created an even more potent formula and the carbs/sugars in the Size On helped Drive
the amino acid
into my muscles (along with the creatine) while I lifted. For $30/kg for Leucine (lasts months) well worth it.
Overall a good product. It's still just creatine so don't expect ridiculous results. Keep in mind my training background I didn't have much room for new muscle growth as I'm near my genetic limit.
If you're training well, eating 4+ solid meals each day (plus 2 shakes/day) then this would be the next supplement I'd add to your program. Again, add 10-15 grams of Leucine (or WPI) to the shake to reap more benefits.