I take ascorbic acid. I never heard anything about it being any worse than any other form. The Linus Pauling institute doesn't seem concerned about it:http://lpi.oregonstate.edu/infocenter/vitamins/vitaminC/vitCform.html
Yeah I take it with 2 grams of lysine, but that might actually be unnecessary since I am on a high protein diet anyway and I'm sure I get way more lysine than that from my food.
Benefits? Well my entire cardiovascular system has improved dramatically and continues to improve. That's obviously a combined effect of exercise and total diet changes though.
Vitamin C absorption is not limited, but as you take more, the percent which is excreted in urine increases. It's a diminishing rate of return. I take a gram at a time, twice per day. I should be taking it three times per day, but I get lazy.
It's just vitamin C. I think it's one of the most researched things out there and it is one of the most beneficial supplements you can take. If I could only have one bottle in my medicine cabinet, it would be vitamin c.