Iwata Hi-Line HP-A Plus

Information

Necessity for fine details.
Has experience airbrushing.
Beginners learn on the HP-A Plus quite often. In fact I usually recommend the A+ instead of the Hi-Line AH (with the MAC Valve).

I tend to believe the MAC Valve gets in beginner's way because it's another thing to try and learn and control. My advice would be to play with this airbrush as is and then, once you've figured out airbrushing you can purchase an eMAC valve
You can sight down the barrel like a gun.
The non-existent cup (hollow in the body) doesn't get in the way of large fingers .

No Cup

Yeah, it sounds silly but that cup can get in the way when you're trying to aim! It also looks sleeker and takes up a bit less space. Makeup artists tend to like the HP-A Plus
Cut-away, pre-set handle

The cut away lets you clean out your airbrush quicker. The preset let's you limit the amount of trigger pull you can have. The preset is quite useful when you have to do the same stroke over and over and over and over.

With only a few exceptions I like all the Iwata airbrushes. They each have their place for users. The HP-A Plus's place is specifically for people who understand that they won't use much paint at any one time--ever! That generally includes makeup artists, fingernail artists, and fine artists interested in the smaller needle and nozzle combination.

These Cleaning Guides links are specifically the ones you need to clean this particular airbrush.

No Place to Set it Down

This is an unfortunate oversight. Somebody needed to include a kickstand! I know many airbrush compressors come with an airbrush holder and there are many manufacturers that make holders of some kind. In fact, you can even make your own with some creative ingenuity.
Tip Dry

Unfortunately EVERYBODY has to deal with tip dry if they use airbrushes. Though one of my favorite methods to eliminate tip dry is to use a slow reducer (the paint won't dry as quickly and therefore won't stick to needle as much. Otherwise you'll need to check out the How to Remove Tip Dry methods in the cleaning guide section.
Bent Needles

If you take the needle cap off to try and get finer details you WILL bend your needle tip at some point. I usually suggest a Crown Cap. Then you can still get the detail but your needle (and possibly the person you're working on) stays safe.

Try this guide if you end up bending your needle and would like to try repairing it yourself.
Clogs

Clean it! Paint dislikes being sprayed and will do it's best to punish you for your outrageous actions! But don't worry, the cleaning guides will help you through these predicaments.
Breaking the Nozzle Threads Off Inside the Airbrush

You are far stronger than the nozzle. Be gentle when twist it in and out!

Try going through these instructions to remove the broken threads if you get careless and break it anyways.