Well it'd be better if I can get a second opinion on this since I am probably the only guy that uses a Tamiya superfine here that's online regularly... I was a Tamiya addict when I was growing up building models, and the Superfine was bought for sentimental values, aside from the fact that no one else had a clue how its performance are compared to its Iwata cousins. So I had to try it out. And to my surprise, the smaller cup was actually able to go through an entire upper hull of a 1/35 panther tank without a problem + leftovers.
The Tamiya "High Grade" is just a name. That's the only line they offer... The 150 is built with definitely good quality (The Tamiya/Iwata/Gunze airbrushes have a slightly nicer chrome coating to them, but that's just bling factors. =P ), I am not gonna question that. My point was that the 150 being a bottom siphon feed airbrush requires you to be using higher air pressure to pick those paint up from the bottle. And all experience ABers know that if you want thinner finer lines, you have to dial down the pressure, most of the time under 10psi. That's when a gravity cup top feed airbrush shines. The 100 series from Badger is an example of that, together with the Tamiya regular double action one and Superfine. Also to me, a gravity cup is a lil easier to clean than a siphon feed AB since you can see everything. So to find an airbrush suitable for you that does all you can throw at it, with the set parameters (what models to paint, paint type choices, availability, location), it'd be Tamiya double action > Badger 100LG > Tamiya Superfine > Badger 150 > Badger 175. Though one thing that people will always mention to you, is that practice makes perfect. An experience hand can use the 150 to do just as nice work as the more expensive ABs. But for starters, I'd still say keep it simple and get a nicer all round brush to practice with.
The price tag of $125 for the 150 set is high as hell due to the import fees and all. Here the set sells for about 90 bucks with the airbrush itself sells for about 60. Tamiyas are around 100 street/ebay price and a crap load more at retail price tag. The hose is something you definitely will need and goes about 10 to 15 bucks for a separate one. The extra attachment you see are just more jars for the airbrush and a full set of 3 size tip/needle set, from which you will be mostly only using the medium size set anyways, as the fine set are close to too fine to be used for even acrylics since it's designed for pretty much ink for illustrations. Does that justify the price increase, you be the judge.
Keep in mind you also need to spend more for an aircompressor that's prefereable with a regulator and a moisture trap, so you need that on your budget list too.
Edited:
Scratch the compressor comment. For a Tamiya AB you can just use any Iwata or Gunze or Richpen compatible airhose since they are the same fitting on the airvalve. The hose that comes with the badger set should be a 1/4 in fitting already so it will fit your compressor without a problem.