The system you've listed seems good for its price. It could play games at resolutions ~ 1400 X 900, @ fairly high settings (but not maxed out on some games). Also, Cyberpower is a reputed name, certainly one of the better ones amongst the custom built systems.
It is, however, true, that you could assemble the same system at lesser costs, if you bought all the parts individually & assembled them (very easy).
Alternatively, for the same price, you could get a better system, again by purchasing separate parts & assembling.
However, if all of this does seem like a bother, then by all means, you could simply get the one you've listed.
Otherwise, if you are interested in building your own & want suggestions, then get back to us