For a more serious slice of Science Fiction I would suggest Terinu, the tale of a mysterious being that has the entire universe after him. So if you enjoy tales about strange aliens, space pirates, and federations than Terinu will certainly be for you.
Then again if you are looking for stuff that is more “out there” I have two other comics that definitely fit, College Roomies from Hell and El Goonish Shive. Truth be told they qualify as being more than Sci-Fi but there are events with mutations, aliens, and shape changing belts, so I made a couple of exceptions. They are both fun comics but on different levels. El Goonish Shive is, for lack of a better word “sweeter” compared to some of the antics in the CRFH. But the storylines in each are well thought-put and amusing. But I have one warning about CRFH, when I introduced this Blog I said that there would be comics that needed a chance to improve in certain areas, if you start from the beginning you’ll find that in the case with CRFH it gets better with age.