I've found that with Star Wars subjects, most of the brands that have done kits have done both good kits and maybe not quite so good kits. FineMolds kits are consistently the best (all their products are well molded for what they are), but some of them can be a little on the pricey side (or in the 1/72 Millennium Falcon kit's case, very expensive). So if you are operating on a budget, that is something to keep in mind. Of the SW kit producers, Fine Molds is the only company that seems to do subjects in consistent aircraft scales (1/48, 1/72, 1/144). Another obsticle is FineMolds kits are technically only available in Japan. Yes, you can find them from certain US vendors, but the prices can vary as some companies just buy them at the yen price and mark them up as though the yen price is considered wholesale (making such kits even MORE expensive). Best place to get those kits for the best prices IMHO are HLJ.com or Starshipmodeler.com. But you can sometimes find good deals on eBay as well if you shop around.
AMT/Ertl did some of their own SW kits as well as reissued most of the old MPC kit catalog (those model kits dating back to the 1970s) when they had the kit license. The MPC stuff can be good or bad depending on the subject. For instance, MPC's Vader's TIE Fighter is considered to be good for its time as it is still the biggest Vader's TIE issued to date. But it is also still a product of 1970s modeling technology. So, you do have to grab the filler tube and work a little harder to get things to fit. AMT hasn't had a Star Wars kit license since about 2005. So the only way to find AMT/Ertl kits today is through secondary sources such as eBay or going to model shows (or joining a model club and make friends with somebody who is selling older SW kits). Every once in a great while you can find older Star Wars kits on model shelves, but that is rare.
Revell is the most commonly available in the US and Europe. To date, they have only done one glue SW kit and that is the Republic Star Destroyer. All their other kits are pre-painted snap models. Quality and detail vary depending on the subject and the scales are all over the map it seems. Plus, the bigger kits have pilot and crew figures that are molded in soft vinyl type plastic (tough to clean seams off of and you have to be careful with paint selection unless you give it a good primer) which I don't like. At least the pocket kits have styrene pilot figures. They can at least be found in hobby shops and the prices are mostly reasonable.
The thing that is nice is original trilogy subjects such as the X-Wing, TIEs and Falcon are very well represented with LOTS of choices from all the companies in various sizes and price ranges. Of the prequel trilogy kits, the subjects are a bit leaner, but aren't too bad. If you want animated Clone Wars stuff, only Revell has done those kits to date.