Hello frrom West Virginia.
Glad you could join us. I have a Janome, altho neither of the models you quoted, and love it. I think your best bet is to go with your local shop. This way you are helping to keep them in business and you have the support you need anytime you need it and tehy probably give free classes as long as you buy from them.
I would be sure you get a walking foot, 1/4" foot and a regular foot. As far as the extended table, I have one and sew with it all the time. Makes for a larger surface on which you have your fabric and that way fabric is not being pulled down and away from the needle and get distorted.
Make sure you read/research all you can and read the small print, ask questions, and see if it comes with a carrying case. Go on the Janome site, e-bay, some of the sewing machine sites, and check descriptions of what these folks are selling with theirs. There is a thread on here of a gal sellling her Janome 6600 for around $1300. This ia a good price even with shipping. That's a machine several of us have and I haven't heard any complaints yet about it.
No hurry to getting the machine you really want. HAve fun and we look forward to seeing your work posted here.