I bought the DS1054Z specifically for the 4 channels. The 100 MHz bandwidth is limiting in that I can only display up to the 7th harmonic of a 15 MHz square wave. Square waves are tough - it takes at least up the the 7th harmonic to get anything that even approximates square.
Sure, but if you know that then it's much less of a problem. [bi]No[/b] 'scope is going to show a perfect square wave.
That may be fast enough for antyhing an Arduino can do but when we get to ARM chips, signal frequencies can get up there.
ARM chips can easily go too high for your 350MHz Tek.
IO peripherals like PWM, SPI, I2C, serial, lights and knobs rarely run at high frequencies but external SDRAM is a challenge as is Ethernet and USB. So, yes, even 350 MHz is limiting. Funny thing is, even a 1 GHz scope would have difficulty with SDRAM and timing is often very tight!
Back when I played with cars, there was a saying "Speed costs money! How fast can you afford to go?". Same thing with scopes.
The problem when viewing square waves that look like sine waves is trying to figure out if you met the setup and hold times.
I guess it is important to recognize that we are talking about an 'entry level' scope that should be capable of doing 'entry level' work. Now all we need to do is define 'entry level' work! I don't think SDRAM is included... I'm pretty sure everything an Arduino can do is included but a 600 MHz Blackfin uC probably isn't. FPGAs might be included it they are emulating simple peripherals but FPGAs are used for speed so it depends on the project.