I realize the thread was started awhile ago, and hopefully the OP has gotten a rig on the air by now.
But just in case, my $0.02 worth:
I started out a couple of years ago with a 7000, and upgraded to a K3 (with the 7000 still in use as a second/backup/portable rig).
I've had a lot of fun with my 7000; it's a nice shack-in-a-box, and the filters and processing are OK. I've worked a lot of DX on it.
I love my K3. There is a big difference in the receiver sensitivity, and the filters are much, much better, and CW just sounds so d*mn sweet coming from the receiver through my headphones. With the 7000, my rule of thumb was "if I can hear it, I can work it". However, with the K3, I hear many more stations, some of which are workable, others which are not.
I live near W1AW. 80m PSK is unusable here on the 7000 when the W1AW CW bulletin is going out because of the dominance of W1AW's signal; I need to tune a few kHz away if I don't want my receiver saturated with W1AW's QRO signal. However, on my K3, with the a tight filter, I've successfully worked 80m PSK within about 200 Hz of the bulletin frequency.
I'm told the receiver performance in the KX3 is similar to the K3.
When the KX3's 2 meter module comes out, I might sell my 7000 and replace it with the KX3+an amp....or I might not. There is something to be said for having a self-contained shack-in-a-box.
Aside from receiver sensitivity and filter performance, my main gripe with the 7000 is the need to use menus. Menus are going to be a necessary evil on most small, portable rigs, but they can be very annoying when you are trying to fiddle to pull a weak one out of the noise. If portability weren't a consideration, there are a few other radios that ought to be on the list.
All that being said, I agree generally with TRJ's comments. While I don't regret my path, it might have been more economical to borrow or buy a used rig to get my feet wet, and then have been in a more informed position if/when I wanted to buy a new transceiver. Any rig and any antenna is better than having no rig and no antenna at all.
(Although, with propagation the past few weeks, one might wonder about that.