Both micro-max A100 & A90 have created a huge demand than they might have expected & mostly all vendors are running out of stock at this moment. One of my friend said, companies like Karbonn, Spice & Micromax purchases re branded phones from china in volume of 50,000 or 100,000 units & their technical team customize the firmware & once ready, they announce via press, then do launching event & start their sales (Also forget their after sales support , hehe
). Perhaps, micromax haven't expected such demand with any of A90 or A100 models.
Both A90 & A100 have got good review so far inspite their average reputation. The phone is impressive for such a budget, but about 10% of buyers complain in various forums about stereo jack issues. Since Mediatek announced a week back, micromax is coming with 3 model of dual core phone, including an improved A90 & A100 (both dual core), the fact might be micromax is withdrawing the sales for A100 & A90 from both online & retail stores. Either they will dump the same A100 & A90 with same old single core processor & launch dual core with extra 2k price, or directly reintroduce the dual core version (withdrawing the existing single core version). So, let us wait & see.
Please wait for 2 or 3 weeks, or maximum of one month, it is official & confirmed that you can see atleast 2 dual core processor phones from micromax (improved A90 & A100) with most of their glitches fixed. Spice Mi500 & Karbonn A24 will also hit the shelf soon.
One month patience will definitely give you few choice of dual core 4.3+ screen phones from micromax (also from spice, karbonn ) in price bracket of 10 to 12K. The only 2 questions are will these dual core phones still have 512 MB RAM (or will they increase it to 768MB or 1GB RAM) & will micromax expand its service support.