I'm an Innova owner, so I haven't tried to give advice on Q-'Nique vs HandiQuilter. But I can tell you from experience that machines at shows are not always set up that well. The vibration you felt could just be due to something not being tightened or level.

Just really wanted to add, that you should also consider what the support is for each of your possible choices in your area. True, many of the long arms may have by web or phone support that actually is wonderful, but just be sure to check it out. Also look at what you will have to do if something you cannot fix even with the online support. Do you have to take the machine off the frame and send it somewhere? This will take time, money, and muscle. Do they have folks that can come to you to hopefully fix it? I was looking at a couple of different brands, had gotten down to APQS or Innova. Finally went with APQS basically, because there were a few dealers in the area and because the demo Lucey I finally got was a great price. And...now 12 years later, I believe I hit the jackpot. Because the wonderful Karen McTavish has a shop about 2 miles from my house and she is just a wonderful shop owner and has inspired many to take up long arm quilting. Oh, and I have yet to have a major problem with my machine, she just keeps on stitching, now that I have more experience, the machine just runs.

I would suggest also joining and reading the Facebook groups for both the Amara and for Grace machines to get an idea of what issues people have and how they are handled, both from a user support and from a service perspective. I spent over a year on both and went with the Amara. If I'd had room for an APQS Lenni, though, that was my first choice. I'd tried all 3 plus the Innova Classic (which must not have been setup correctly at the road show, because the handles vibrated so much it made my wrists hurt). The Lenni was the best of the bunch to me - it's frame was just too deep for my space.

I have a Handi Quilter Forte ( 24”), traded in an Avente (18”)for it, both with Pro Stitcher. The only trouble I’ve had with them was caused by operator error. Have used the Help line and they were very good and patience and also have called my dealer. They were great too. The Pro Stitcher Premium is far better than the older versions of Pro Stitcher. I checked about sending it in for maintenance and it is 2 years or 10 million stitches whichever comes first. Mine was way over two years when it had maintenance. My husband loaded it in the car and I dropped it off and picked it up a week later. Cleaning it helps keep it in good shape. I love mine and the best advice is bought as big of longarm as you can. The extra 6 inches on mine made a big difference in the digital patterns I can use. You won’t regret it but make sure you can reach everywhere.

Just wanted to add
This is the time of year when you might be bombarded with great deals...black friday sales have already started in my inbox. If you find a dealer that will work with you, you can negotiate a pretty good deal for yourself.
I bought mine at this time of year, several years ago, and the dealer threw in every advertised extra that I brought to her. She also offered 1 year of classes for free and I joined a monthly group that she sponsored to help newbies like me overcome the initial intimidation that some people feel with a new machine.
We actually became great friends.
Really wish she hadn't moved away....
Here is an example of the ads I'm getting:
https://handiquilter.com/purplefrida...cid=3319ebfcdf

Last question first:

I bought Q'nique 21 and QCT Beginnings because it was half as much as similar throat size of HQ, and Pro-stitcher did not offer tiers like QCT does. If I was going to start a business quilting, I might have made a different choice. But that would make quilting WORK and I am done with WORK!

HQ16 bought used. It was not stitch controlled, but the PC Quilter computerized system I bought with it moved the machine at a steady pace, so it wasn't necessary. For me, size 11 stich worked best. HQ16 was basically a mechanical machine with some computer control. My husband was able to clean and maintain it, thank goodness.

Q'nique 21 - Stitch size - I generally use 10 spi and have beautiful stitching. Size can be adjusted smaller or larger, but not sure of he range. I'll look it up tomorrow. Tension is everything with stitching, no matter which machine you use. My Q'nique and I have worked that out. I replaced the bobbin spring with a Bobbin Genie; it was like a miracle occurred!

Handles: I don't use handles as I have nerve issues in shoulders arms and hands, so moving the quilt for any length of time could become tortuous. That's why I purchased a long arm after quilting one baby quilt on my domestic machine.

I started with a small Pfaff machine on a Grace frame and then upgraded to an HQ Fusion about 7? years ago. Bigger throat space is very important.

You say you aren't planning to go the computerized route, but have you done much free motion quilting with a longarm? It's not as intuitive as you may think or be led to believe by watching experienced longarmers. It takes a ton of practice!

I got my HQ from an amazing dealer who came to my house and set it up and gave us a 2 hour lesson. We then had two FREE all day lessons from them--one on how to load and all the steps involved in quilting an entire quilt and another day of just learning how to use the software. I took my computer savvy dh to that class and for a good while he was better at this than me!

My one caveat is that the ProStitcher software can be frustrating! I quilted this week with the lastest update and it had me swearing and ready to chuck it thru the window. But then my dh came along and had NO issues. Sometimes technology hates me (and I just need to shut down for 10 minutes and let both of us cool off!!)