Selected answers from the Dumb SEO Questions G+ community.
Travis Bailey: That`s usually true. When it comes to keyword tracking, SEMrush doesn`t track a lot of lower volume keywords. Like say, for instance `plumber *someSmalltown*`. They`ll track it, once you`re paying to track the keyword though.
I like aHrefs a lot. But honestly, you want as much link data as you can possibly get. So if you`ve a client that requires a large link analysis, you definitely want more than one source. Best to sort it all out in spreadsheets after multiple exports, then. But all around, aHrefs is very good.
I definitely prefer both of those tools for initial glimpses into the murkier portions of projects.
Michael Martinez: If you`re going to use tools for research, then the more tools you use the better because no tool is perfect. It`s more difficult to get diversity from the keyword research tools, and they are using paid search keywords, which is a very biased data set. If you`re interested in developing content for the long tail of search you`ll have to dig really deep. The backlink tools all come up short so if you`re really studying backlinks you must use Bing and Google`s backlink reports at the very least, but the more 3rd-party tools you use the greater the "outside coverage" you`ll get.
Selena Vidya: I`ve preferred SEMrush for keyword research, especially with how they`re slowly improving their Keyword Magic discovery tool, although Ahrefs has become a pretty big competitor with their "clicks" estimation and traffic potential data. I *am* looking forward to seeing SEMrush introduce keyword research around YouTube, as I previously used Keyword Keg for that but no longer subscribe to it.
Si Quan Ong: We just released keyword data for YouTube, Amazon, Bing, Yandex, Baidu, Naver, etc. for Ahrefs Keywords Explorer :-)