Today I compared the following models: Tascam US 2x2-SC (I noticed that the model some posters recommended earlier was 20x20, but, as I said in the OP, two inputs would be enough for me), Focusrite Scarlett 2i4 G2 (as I said in the OP, I need MIDI ports), PreSonus AudioBox USB, and Steinberg UR242 and UR22mkII. I didn’t know that these interfaces were so inexpensive. I said my budget was $500 or below, but since my washing machine and refregerator are likely to break down soon, if one of these inexpensive interfaces could work fine for me, it will be very helpful finantially.
 
Among the candidates, AudioBox USB is unfortunately unlikely to be my choice, since the headphone jack in on the rear panel (and also it’s 44.1/48kHz only and the gain range is 0-35dB, which isn’t very wide). Latency-wise, Scarlett (generation 2) outperforms the other candidates, but the company/agency that sells Focusrite products here in Japan is, IIRC, notorious for providing poor support, and their product page for Scarlett models lacks a lot of information (so I had to visit focusrite.com to find all the details).
 
So I’m more likely to go for either US 2x2-SC or UR242/UR22mkII. I sent email to both TEAC (which sells and supports both SONAR and Tascam interfaces here) and YAMAHA to ask about some features of the products.
 

icontakt

JohanSebatianGremlin
And what I'm realizing is I've got three requirements (low latency, driver support, under $500) and I need to pick any two. You can find lots of solutions that will tick off two of those boxes, but none that tick all three.

 
How about Scarlett 2i4 G2? It’s round-trip latency is as low as 2.74ms according to their site. And it’s under $500. Poor driver support?
 

From what I understand, Focusrite is pretty good with driver support while the box is in production. But once production stops, its hit or miss whether they decide to keep writing new drivers for it. If that happens, you can end up in a situation where your I/O box is a few years old and still works perfectly, but you've upgraded to a new OS and because they won't write drivers for that OS, you're forced to go shopping for new hardware.

Also beyond that, if you browse through the forum you will find what seems to be a fair number of threads related to issues with Focusrite interfaces. I have no doubt most work fine and to be fair, there are lots of threads related to issues with interfaces from almost every manufacturer. What I'm saying is, focusrite is definitely included in that group of interfaces that people can sometimes have issues with.
 
Whereas if you search for RME, you find very few threads here with people asking for help. And you also find lots of posts from people who say their RME box has never given them a problem. If you're looking for bulletproof reliability, it just seems like RME is the safest bet.