what do you have now and what features are you looking for, wider harp space. Are you having difficulties with your machine. All of those machines are great machines with good ratings, but what is you budget because a tiara and an NX-450Q are a wide price range. I like my brother dreamweaver and the sewing quilting one might be in your range if you are looking at the tiara. It has a wide harp, awesome lighting, and the muvit foot can't be beat, it is awesome. I did have the babylock espire which was the brother qc-1000 which is a couple models up from NX450Q and is now replaced by the laura ashley and I would also recommend that as well. The PQ1500S is popular and if you have another machine it might be a good choice for you