Well... after having tried a bunch of different mice: G400, G700s, G9x, Razer Deathadder, Razer Taipan, Razer Imperator, Razer Abyssus, Razer Lachesis, Steel Series Sensei, and Mionix Avior (which came out just recently)...
I'm going to have to pick the Razer Taipan as my favorite (of course, this is just my personal favorite; everyone's opinions are different). Now, is it the PERFECT mouse? No. There is obviously potential for a better mouse to come out in the future, but for now, the Taipan is my personal favorite.
To me, the shape is the most important thing, and I just really, really like the Taipan's slim and narrow shape. It just feels better to me to have that narrow form factor, while I'm gaming and moving the mouse all over the pad, than having a bigger, filled-out mouse like the Deathadder (although the Deathadder comes a close 2nd or 3rd among my list of mice). The narrower, and slim form factor allows me to change, and have flexibility over, my grip while the mouse is moving.
With something bigger like the Deathadder, and the worst, the G9x (with its fatter grip), I'm kind of always forced to have one specific grip the entire time I hold the mouse. Luckily, the Deathadder has nice curves so it doesn't cause much fatigue, but with something like the G9x (with fat grip), my grip just gets tired and worn out over time. In fact, fatigue and getting worn out seems to be a theme for me (although it may be different with other people) with all the Logitech mice, such as the G700s and G400.
Which is unfortunate, because Logitech has made amazingly comfortable mice before, such as the M500. It is still in production, but it unfortunately doesn't have DPI adjustment, which is why I don't use it.
That said, yes, I understand the Taipan has that laser sensor with hardware acceleration built-in, but... I've always secretly believed it really isn't that big of a deal. I see pros use mice with the laser hardware-accel sensor all the time, such as the Sensei and the G9x, so I have to assume it really isn't that big of a deal. I really won't make judgments against the acceleration built into the sensor, until I really see and feel the affects of it in-game. But to this day, I haven't yet, so it's not something I'm going to consciously avoid.
Also, I do think the dual sensor system used by Razer for the Taipan mouse makes the mouse movement a little smoother for a laser mouse (this has nothing to do with acceleration; I'm just mentioning the smoothness in this paragraph). As I understand it, optical sensors and laser sensors inherently feel different on screen, but for some reason the Razer Taipan's laser sensor seems smoother than other mice that use the same laser 8200 DPI sensor, such as the G700s, Steel Series Sensei MLG Edition, and the Mionix Avior 8200. I just used the Mionix Avior a week ago, and I immediately noticed the difference when I switched over to the Taipan.
Again, this probably doesn't have anything to do with the acceleration, but when talking about the overall smoothness of the cursor movement on the screen. The Taipan seemed to be smoother compared to other mice using the same laser 8200 DPI sensor, and I think it has something to do with the dual sensor system by Razer. IIRC, the dual sensor system employs an optical sensor in conjunction with the 8200 DPI laser sensor, and I think that is somehow helping smooth out the movement.
That's it for my opinions on the Taipan for now. If there had to be a perfect mouse for me, it would have a shape similar to that of the Taipan, but more "ergonomic". It would have to be just as narrow and slim, but also have curves at the same time for comfort. So, maybe something like a hybrid of the Deathadder and the Taipan.
Interestingly, the M500 by Logitech comes really close to that shape. All Logitech would need to do is add a DPI adjustment to that mouse, and they would have a pretty decent mouse on their hands to sell to the public. But, no... it seems they are only interested in making mice with wonky shapes (G9x, G700s) to mark-up and overprice as "specialty gaming mice". Then again, you could say that about every other "gaming" mouse manufacturer out there, including Steel Series, Razer, and Mionix.