Hi, if you'd care to use the search function (in the top right corner of the main toolbar) you can see what has been written about this in the past. It's a common question.
The RG7321 is a pretty basic instrument. Because of the binding there are often harsh fret ends which make playing them uncomfortable. Again because of the binding, it's more difficult to level them without marking the binding.
However, once the pickups are replaced with aftermarket models suited to your specific needs, the 7321 can be a good solid guitar. If you can find a 2nd hand one, perhaps with suitable upgrades, for the right price, they can help a player decide if it's worth investing in a more expensive 7 string instrument.
The 7620 (floyd) and 7621 (hard tail) are much better instruments, as is the 1527 Prestige, but are more expensive.
Tuning a 6 string B E A D F# B with heavy strings (60 - 12 for rythmn playing or 9-52 for lead) might help you decide if you can make use of the tuning. The benefit of the 7 is you can play in these lower tunings without losing your high E string, and the expressiveness of your lead playing, in my opinion.
Try as many instruments as you can before choosing one!