As a long time Rogue Trader myself, I cannot recommend it enough. Although I own and have played Dark Heresy, Deathwatch, Black Crusade and am about to (hopefully) soon receive my copy of Only War, I must say that Rogue Trader offers a really unique and satisfying experience, both as a player and a GM.
Anybody who has played BFG will find many similarities, as BFG is obviously the inspiration for the space combat side of the game. The game is very solid and offers infinite varieties of ships and scenarios, with a single caveat to mention: the game, being a roleplaying, favours the underdog.
In BFG, a fight between a cruiser class vessel and a single escort would be brutally one-sided. In RT, if that player was the escort my money would go unconditionally on the character. If you want a more true to BFG/fluff experience, I would recommend doubling the hull integrity at the very least and using the squadron rules from battlefleet koronus, the ship supplement of the game. You should also consider Into The Storm, which is a variety pack but does contain some very nice ship hulls/components/rules.