If you asked me a year ago whether an Epiphone sg Pro could be as good as a real Gibson sg my answer would have been an outright no. However I am now in a position to question that original judgement and have to say that with work and the right choice of pickups you can get pretty close and perhaps even go a step better than a standard factory Gibson. The problem with Epis is that they are chucked out the factory off the production line without much care and attention but mechanically they are perhaps 80% or within 20% of being a Gibson. What Epiphone do not do is the labour intensive work that is required to make a real instrument because it is not cost effective for them to do it at the price point at which they intend to sell for. If you are prepared to do it yourself or get somebody who can do then you might find that you can get pretty close to the sound and playability of the real thing.
An Epi sg has the potential to be as good as a Gibson it has the right tone woods and construction is good. However the wiring of the pickups is particularly bad (uses plastic molex connectors another shortcut option brought in to speed up production and to reduce costs and craftsmanship) and should be rewired totally to a new schematic of 50s style sg. You will also need new capacitors. A better neck pickup preferably alnico II magnet. The next thing you will need to do is level all your frets. I would say that 75% of mine were unlevelled. That’s a lot of fretwork to do but it is the key to getting a real instrument. These are the labour intensive tasks that Epiphone will not do because it would make the sg pro almost as expensive as real Gibson. This is the attention to detail that Epis lack and which give Gibson the edge. Epiphone try to disguise this by sending their guitars out of their factories which overly high actions which when you try to lower them has the strings buzzing on the frets all over the guitar neck. A high action makes the guitar awkward to play and uncomfortable. This is very frustrating and will soon have you either giving up on the guitar or selling it and then dreaming of spending the extra cash to get a real Gibson. My advice is just don’t do it and don’t give up on it. True there is a great deal of work to be done but once you know what the problems are these can be sorted out with time and effort.