what is the better airbrush? i'm planning to buy a back-up since my badger 150 needs an overhaul...

i need your feedbacks on the 2 airbrushes... thanks!

My personal suggestion would be look at a the Badger 100 series as a replacement/back-up for the Badger 150.
I use a Badger 100G for 90% of my airbrush work, and an Iwata HP-B for fine detail work at home. I'm 100% happy with both. I also use a Badger 150, first airbrush I used, and learned on, back in the early 70's, and a Passche VSR-90, these I keep at work for any airbrushing I do there.

Now the reason I would suggest the 100 series Badgers. (there are several in the series, with different features so I suggest you check out the Badger website)
1. You've been using a 150, so changing over to a 100 isn't a big deal. You already are use to a double action, and the 100 series are double action. If you get the larger 100 series with the covered cup, spilling isn't a factor to worry about. (I prefer the smaller uncovered cup, and haven't spilled it yet, since it uses/holds less paint, less wasted paint, and as a top feeder a snap to clean)
2. Being another Badger, it uses basically the same parts as the 150. The heads and needles are the same, and you probably have some of these already on hand as spares. They are also more ready available if and when replacement parts are needed. (90% of the hobby shops I go to carry Badger replacement parts, I've yet to see any with Tamyia replacement parts, a very important factor when considering a replacement or new airbrush) The cost of the replacement parts needs to be considered also. I don't know the cost factors involved over in the Philippines, but here Badgers parts are a lot cheaper than Iwata parts, and more ready available. (see note about hobby shops carrying them, I have to travel to the art store for my replacement Iwata, and Passche parts, or do mail order.... which increases the cost with shipping)

Since I don't own any Tamyia airbrushes can't comment on their quality, but have been told their higher end ones are made by Iwata, and if so, then they are excellent airbrushes. Again the important factor is the availability of replacement parts, their cost, and service.