I also got interested in Amigas about 2 years ago. I'd always read about them in magazines and heard mention of them in demo competitions etc but apart from viewing some demos on YT I'd never actually used or even saw one in person. I won an auction for a non-working A600 and managed to get it to work by doing some minor motherboard repairs. That was my introduction to the Amiga world.
I chose the 600 because 1200s can get very expensive and I wasn't quite ready to invest big money yet. Even just a base A1200 can get spendy even before you get into accelerators - and the A600 has the hard drive and PCMCIA support that makes it easer to use today than an A500. A500s are more compatible with older software (which seems to be where the bulk of Amiga support happened) but you can usually get an A600 to run anything written for an A500 with a few tweaks.
Of course the upgrade bug bit me pretty early and I ordered a bunch of stuff from Amigakit. Firstly just a CF hard drive kit but eventually I ordered a full-re-cap kit, the memory upgrade and even the VGA output adapter. It's made my A600 quite a fun little machine.
One thing that surprised me with the Amiga - having never used one before - was how poor the hard drive support is/was. Coming from a PC background where even the oldest CGA games either directly supported hard drive installation or at least ran fine when manually copied over to hard drive, the level of hard drive support struck me as fairly poor on the Amiga. Most of the games I tried did not support hard drive installation at all - it's only through the WHDLoad project that you can run most Amiga games from hard drive. The floppy drive in my A600 is noisy and slow but most games seem to be designed to run purely from floppy - not surprising I suppose since so few A500s had hard drives, but even later games continued the trend - mostly for piracy concerns I suppose.
My A600 can only run one or two games through WHDLoad unfortunately, because the application really needs so-called fast RAM. The Amiga uses two types of RAM, fast ram and chip RAM. As I understand it fast RAM is what we PC users would just call normal RAM, but chip RAM is RAM dedicated to the Amiga custom chips (sort of like VRAM on PC), but which runs slower than the CPU itself. The A600 can only support 2MB for chip RAM and no fast RAM unfortunately. That means unless I invest in a fairly expensive CPU/RAM upgrade card for my A600 I'm SOL when it comes to most games via WHDLoad. I may eventually get the upgrade - in fact there has been quite a burgeoning industry of upgrade cards for A600 recently so I might get one of those when they come available.
What I did instead was import an A1200 part-by-part. It works out cheaper to buy parts sometimes than a complete A1200 - especially when I can re-use the drives and power supply from my A600. The A1200 is a better machine all-around. It also does not come with chip RAM, but upgrading it is easier as far as I can see and it comes with 2MB chip RAM already installed - as opposed to the A600 which had to be upgraded to 2MB. The A1200's CPU is only slightly faster than the one in the A600, but speed improves when fast RAM is installed and the A1200 also supports AGA (256 colour) graphics. Unfortunately AGA support is not brilliant in the Amiga software library since the A500 was by far the most successful model, but AGA is a nice bonus for software that supports it. That CPU upgrade linked to above is an excellent way to upgrade an A1200 - although the VGA output option is apparently not as reliable as the one for the A600.
I think overall the Amiga is a lovely little platform, but I did have to temper my expectations a little based on the rave reviews the hardware gets online. It's basically an excellent machine from the late 80s to early 90s. Since I started my PC career in earnest with a 386 PC with VGA, Amiga software can look a little basic to me, but if you dig a little you can find some really excellent software for the machine. Turrican and Turrican 2, Cannon Fodder, The Chaos Engine and The Secret Of Monkey Island are all excellent - although adjusting to the fact that most games only support one joystick button can be painful.
If you want to find out where the better versions of so many early 90s DOS ports came from I'd say the Amiga is a platform well-worth investigating.