I personally tried luekic....it was not worth the money. I spent $70 on that stuff and I actually regret buying it. My buddy is on a cycle of gakic and sizeon right now, his bench went up from 205 to 225 within a month, but again I do not think that it was the gakic that did that for him. Sizeon is a really good product, it is creatine based but its delivery system is alot better than most other creatine based products out there. Also, if you get the luekic or gakic...get the pill form...the powder taste really bad. Probably one of the worst tasting supplement I've tried.
Soler....a high protein/high fat diet is not bad either, but its all depend on what are your goals?. Are you trying to get gain weight or lean weight?. Also are you lifting for strenght, endurance or muscle mass?.
Generally the best way is to gain as much weight as you can...meaning eating alot of calories..mainly from protein, complex carbs, and healthy fat. At the same time, have a good work out plan. Try spending atleast 3 times a week at the gym, and about 2 hours each time. You generally do heavy weight between 6-8 reps for 3-4 sets. Do this until you reach your goal, than you can cut up and start doing cardio while changing to a healthier diet.