I'm looking for a mid-range arranger keyboard that I can afford, and here in my country there aren't many alternatives.

The only i-series available is Korg iS50. I've heard that this has already been replaced by the newer iS50B, but I don't know what's the difference between the two. If it's a big difference, maybe I'll ask the dealer to bring it in.

The other alternatives are KN1600, PSR640/740, PK7, and old Kawai Z1000. I'm personally leaning toward Korg's and Yamaha's.

Maybe some of you out there could make the distinction much clearer to me. I would like the comparison between iS50 and PSR640 since comparing iS50 to PSR740 would be much unfair...

Opinions about the other models at this range are also very welcome.

Thanks
Poonna

Poona,
First of all there is no difference between the is50 and the is55 except for the color. The 55 is black vs the 50 being silver. The only difference is that the newer 55 has a retail price in the USA of $1300.00 which is a little less than the previous is50.
As to the comparison of the 640 vs the 50, the major differences are that you can program your own sounds on the Korg and the Sequencer has better editing functions. You can individually change anything one note at a time on the Korg and you can record in real time or step time including realtime overdubbing or replace mode. Basically, all the features of a more pro Korg keyboard are on the is50.
Now, here is my opinion. The Yamaha has easier to access functions. There is a 0-9keypad and a data entry wheel and the display is much clearer than the Korg. On the Korg I dislike the rubber buttons which tend to stick if you push them down on one side, and it is very difficult to know which sound or style you a choosing since there is no name showing a list on the screen. You must have a chart of paper next to you or memorize every style and sound in the keyboard. The Yamaha lets you search by catagory or scroll through a list of all sounds and styles. I also like the sounds better on the Yamaha, especially the acoustic piano. One other big difference is that on the Yamaha, you can record your own user styles and on the Korg you can only load user styles from a floppy disk. This becomes limited if you cannot find the kind of styles you like to play.
You probably wont like the sequencer as much on the Yamaha because you must put a floppy disk in to record and everytime you finish recording a track you have to save this to disk in order to hear it.
I would say it will be important what features you need to have and make you decesion based on your needs.
George Kaye
Kaye's Music Scene
Reseda, California

I sing, so the vocal harmonies on the PSR 740 have been wonderful. I play a lot at nursing homes and for mental retarded kids. The challenge of playing for old people is unless they're really stimulated, they fall asleep. The staff doesn't like it when all the old people are falling asleep while you're playing. Well very few old people fall asleep while I'm playing the PSR 740. The styles are hot, the "sweet voices" sound so real (at least to me), it's very very easy to play and change styles and voices. The only downside is that apart from the 160 voices that come with the unit, you can only have three (what a pitifully small number!) user styles onboard at a time. Others have to be loaded from disc. You can load from disc during a performance (it doesn't take long), but it is kind of a hassle. And you can't use the one touch setting to get an appropriate voice for the user styles. You have to search them up. So to play from a disc takes about 10-20 seconds to search for the style and load it and find a voice for it. I bought the PSR 640 and then I exchanged for the PSR 740. Believe me, the extra poliphony, vocal harmonies, voices, modulation wheel, simple intro, simple ending, and organ flutes are worth it!

Haven't seen the Korg, but the 740 would be hard to beat in that price range, particularly if you are a vocalist.
As Beakybird and George said, it is extremely easy to learn and operate. I feel one feature that I found outstanding is often overlooked, at least in these discussions.
It has a "Groove" button that effectively doubles the number of styles. For instance if you are playing Style 49, 4/4 rock and roll, you can change it to a shuffle with the touch of the Groove button.
I miss that on the PSR9000. On that keyboard you must go to a style composing page, make the groove changes, and then save to disk or flash rom.
Don