Tamiya has gotten better with age. A while ago I ordered a discontinued Lamborghini Countach from Tamiya, and it was pretty good but a little disappointing compared to the newer ones I have built.
For example, Tamiya's Ferrari Enzo kit is really quite excellent. It comes with masking for the windows so you can paint a black border around the interior outside edge, as well as real wire mesh to cover the intakes which looks supercool when it's all done!
I only build Tamiya because their kits are the best-looking when completed. They resemble the actual cars to the last detail, and use real rubber tires and multi-color plastic in their kits. The instructions are mainly in Japanese, but there's still some English - enough to get by at least.
In the newer kits - as well as all of their race car kits, you build everything. From the shocks and struts to the brake rotors and pads to all the minute details and pieces of the engine. They don't cut corners and the pieces are always professional-quality in terms of etching and details. I've never opened one of their kits, even ones that are 10 years old, to find a warped or broken piece.
Of course, then there's the price. If you buy from a good, honest hobby store, they run from about $35.00CDN for the lower-quality ones to almost $70.00CDN for the top of the line ones (usually the only ones that cost that much are whatever they have that is brand new, like the Enzo and now the Porsche Carrera GT). The Race cars I mentioned in the list above usually go for around $40CDN.
BUT DON'T FORGET ABOUT ONLINE AUCTIONS! There are plenty of sellers on certain online auction sites that sell many Tamiya kits for dirt dheap, mainly because they're old and idscontinued. Many of these sellers are from Hong Kong and Japan, though, so the shipping can be a bit high. I recommend Tamiya, no matter what the cost. It's always worth the extra few bucks!