Hey there,
For the Tiger I, you have many, many options....
I have used the Eduard for the Tamiya Early/Mid production tank... and like it a lot.
The Aber set for the Early is very thorough - thoug it is also very, expensive ($50+)
For the Late Tiger 1, definitely Aber all the way...
For the King Tiger,
Either Aber or Eduard, it's very close, just be careful which set that you buy with Eduard as the had some earlier sets for the "original" Tamiya King Tiger. I am currently about half way through with Eduard Sets for the Tamiya "Production" KT... it's been very easy to use and quite complete.
The Royal Model sets for the Tigers are starting to show their age... however, they are still an excellent value. These sets also include some extra bits in resin so, you might have an easier time of it.
I recently used the Royal Model Tiger I Fender set... it was very nice - here's a shot of the model showing the parts that I used.
Later,
Tim