It's the most popular right now. Be prepared to set aside a fairly decent budget and you will do well! You need a mix of both banner ads and text ads in your campaigns.
"best" is very subjective. As far as PPC forms of advertising goes, Google is the search engine used the most so it makes sense to leverage all that traffic with Adwords. But you can use others. Your target market may congregate on Facebook so it would make sense to use their PPC service. In my opinion, Adwords does a lot that many others don't, or do poorly or not as well as Adwords. That makes them the best PPC service around. But don't leave money on the table. Use others too.
If you want traffic as soon as possible then use adwords but you gotta pay Big G. If you want free longterm traffic then SEO is the solution, but it takes time..
I lost $4,000 in 5 months with adwords. So you can say i dont like them. The one "winning" campaing i had that made me $400 profit a day was banned. I just tried to milk the losers to long...lesson learned....it only cost me 3 mortgage payments
Adwords is definitely one of the best options for advertising online. If you can figure out the "correct" combination on keywords, geo-targeting, ads and web site landing pages, it is the most cost-effective ways to market your products/services.
Basically Ad Words is the simple way for advertising your product. But you need to figure out proper keywords combination!