Hi Michael, welcome to Nimble!
From a quick glance it looks like these switches will most likely cause problems - it has a low buffer memory of 3MB for the whole switch, so it's highly likely that performance will be hindered not just for the array, but for everything connecting through the switch (as it's a shared memory), and a few calls to support.
Of course it's all relative to how much I/O you are going to be putting through the switches in the first place... but in my view it would be sad to invest in something as high performance & low latency as Nimble and run it through a pair of low end switches like this
We do have a list of known good switches for both 1GbE and 10GbE so feel free to ask your local Nimble SE what would be a good fit - in general, we do recommend staying away from Netgear/DLink/Linksys and the like. Even some of the low end Dell and HP switches will not yield good, consistent performance.
I think Nick already answered a lot of your concerns, but during Nimble NTSP training 2001-I we discuss this in more detail. Here you can find a slide on the recommendations we do in regards to iSCSI switches :
The last line is very important and often the problem with low-end priced solutions.
I think Nick nailed it. Just to add some of our specific experience, we've had really good performance running Nimble through both Cisco and HP switches. Even the mid-level HP 2900 series switches performed very well for us. We've also had good success with the HP 5400 series chassis switches. Since you're using Netgears I'm going to go out on a limb and guess that you might have some pressure on you to not spend much on this stuff. If that's the case, I recommend taking a hard look at the aftermarket (read: ebay) HP 5400zl series chassis switches (the smallest one is something like 4 or 5U). They're very inexpensive because the aftermarket demand for them is really low (the aftermarket for non-cisco aftermarket chassis switches has always seemed very weak), IMHO their feature-set rivals the cisco stuff (unless you have some incredibly complex requirements), and they're documentation makes them easy to implement for just about anyone with basic network skills. In another life I was forced to go down the aftermarket path with HP switches and found they still honored their lifetime warranty and I was able to add an onsite support contract on top of it.