Here's my fourpennorth!
I have seen the Janome Continental up close and personal and it is HUGE. But, I have the Janome 6700P (its rather smaller brother, but still quite large) and although it sews well, it is a tricksy little beast at times. I will say that the Janome accessories and feet are not particularly well made or robust, and I don't think would stand up to a lot of very hard work, despite the actual weight/size/speed of the machine. I am not a lover of it's drop in bobbin. Yes, it is easier, but the bobbin cases themselves are quite fragile, can lift out of place at a moment's notice and develop a huge gouge in them (this can be filed down). So, I think the Continental would be a NO from me.
I have also used my friends Bernina 7 series, which is also a beast of a machine, very stable, but best of all, very well made, the feet are a work of art. Yes, they are expensive but are way, way better than anyone else's, bar those belonging to an industrial machine. I had a 4 series Bernina, which I sold to buy the Janome 6700p, as I wanted a larger throat space, an easier to use thread cutter button & much larger foot pedal that didn't walk across the carpet. I got what I wanted, but there were things that the Bernina did which were SOOOO much better!
The Bernina I chose was 5.5mm stitch width, and the Janome has a 9mm - I have found this sometimes leads to 'tunnelling' unless I use a decent stabiliser underneath, so I have to say I haven't bothered with them much.
Both had a lot of fancy stitches, which I dont use, I do a lot of free motion embroidery, which they were both pretty good at. I preferred the Bernina for straight stitch piecing, despite the Janome having the HP foot and needle plate, which in turn is nowhere near a match for my straight stitch Juki!
I don't know much about Pfaff, apart from I had a Performance 5 for a while and hated it!
A good thing to do is to do a Facebook search for the machines, and there are lots of owners out there that will share their problems and tips - I learnt loads about my Janome, having had a few problems with it, to find out loads of others did as well!
Regarding the embroidery bit, I think I would purchase a dedicated embroidery only machine, and see how that goes!
I wish you the very best of luck and fun with your decision, whichever you choose!