Is the Select mic much better than the Table Mic II?
Table mics can create network of them, all in table mode, if you need more than one to cover the area.
Selects cannot do that, if they network, only one stays in table mode, others go to lapel mic mode, so point upwards.
@RogerPM said that they have same tech, and I have impression that they do have other differences as well.
Select is advertised for restaurants while table mic for professional meetings.
With select you have beam forming feature, and you also can say which direction it should focus on as sound source while table mics only can get everything, expecting non competing speakers situation.
Table mic 2 has option to get people closer to the mic or further away, so in some sense they handle background noise in that way.
Select’s beam forming doesn’t mean you will hear only that direction but others will be a bit lower. A bit. That’s the keyword.
If you have bunch of people competing while talking, eg kids in classroom while doing some activity, I’m not sure if any would help. Because you will still hear everything.
Maybe pen will be the best, but for it, don’t expect it’ll catch just one person out of the bunch speaking if you’re too far away with pen. Pen on table mode is poor compared to those two above, so, I’m talking only about interview mode.
I’m not sure if any can work in classroom where everyone speaks at the same time and is busy. So, it highly depends how your classroom looks like. Eg how close you need to come to be sure you’re capturing the person you want.
For quiet, I’d probably use table mics if someone else is paying, since they can be all around.
Select is one table only. But it’s cheaper device, at least here (still insanely expensive though).
I didn’t test table mics, so my conclusion is from the papers. Pen and select I have, pen I’m still trying to find a use case. I bought regular pen on ebay and select iN new from my dispenser (to get the receivers, you need them just once). Pen in I couldn’t test since ‘Germany is to small market and pen iN isn’t available’ 
To get some perspective, what’s your wrs in quiet? Any measurements done for noise, like quicksin?
First number sets some expectations from aids, another tells how desperately you need mics and if they can help or not.
Aids give 3-5db boost for speech in noise, mics supposedly give up to 10, but if you need more than that, no device can really help you the way you’d like. However still, they’ll make your brain’s job somewhat easier, but it’s still gonna be hard work.
Also, both aren’t that great when noise is other voices, that’s the hardest situation any hearing device is in.
What I’m saying is, it is possible that you’ve reached tech plateau, and more ooomph just isn’t available. In that case, point would be with which of those available, your brain can work better with eg where are you maybe a bit less tired, or some other criteria you notice as important to you.
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