Check out the Wood River planes. I have two so far, a #4 and a 6. Wonderful tools with very high quality. Bottoms and sides are square and pretty flat. Irons are excellent and not too much play in the adjuster. No matter what plane you buy, you're going to have to do a tuneup, make sure the bottom and the underside of the iron are flat. I am very happy with them and if you check out the reviews, you'll find they come well recommended. If you get one that is out of whack too far, you could probably return them or get a replacement. The company is clearly working to earn and keep a strong reputation.
I do have a Stanley Sweetheart block plane that required almost no tuning other than a final blade sharpening and flattening. But I've heard they are a little spotty on quality, so make sure if you buy one that you check it out thoroughly before you tune it so if its way off or too rough to suit you, you can exchange it. I think Stanley is putting out the Sweetheart versions to try to restore its tarnished reputation. The company that bought them sure did a number on what was once a great brand.