I will discuss the Janome 3050 since I own that one. It does NOT have needle up and down. It is a 3/4 machine. It does NOT have a large harp. I would never try to "quilt" a quilt top on my 3050. I did not buy it for that purpose. It is an older model and Amazon had it for $449.00 the last time I looked. They do not have any on Amazon at this time and they are not sure if they will have. Probably discontinued. I paid $499.00 for mine in 2006. It is computerized. I love my 3050 but it is my portable machine to take on vacation or to class. It is great for piecing/sewing.
You will not find a large harp in your price range. My everyday machine is my Janome 9900. I do use the embroidery once in a while but I mostly sew on it. MSRP is $4,999.00.
Now, my next opinion has to do with "go to a large show". If you do NOT do your homework before you get to the show, you may NOT get that infamous "deal" on a machine. The top machine dealers vend at shows and they know how to sell machines. You are all excited and they can read you. ( you had better know general pricing, features, bring your list of which machine you are TRULY interested in because you did a lot of research online, on vendor websites, read reviews, compared/listed features, etc. asked friends....) honestly, I bought a serger at a huge show and my regret was that I did NOT know pricing beforehand. Did I get a "deal"? To this day I am not sure. It does not matter because my seger was shipped from their store that same day. Too late to back out of the deal. I like my serger but rarely use it. My bad.
What I did NOT get was a local dealer for support, classes, one on one instruction, etc. You will not get a lot of time to just play on a machine at a show...IMHO. if these things do not interest you then go shopping at a show. Frankly, I feel bad that I did not work with a local shop.
Buying a machine is like buying a car. Go to vendor sites and start making comparisons. Go into shops armed with info. Expect to make compromises from one machine to another. Best of success in shopping!
sandy