If you are talking about students, they would buy which ever is the cheapest and most affordable. Even if it looks like a brick from 16th century. If the instruments are provided by the university, and if the student has a choice of choosing the better looking one, then yeah they would choose the better looking one. Because they might think its newer and must give better readings or must be more accurate. Also they might think its harder to use if it looks to fancy. Professionals on the other hand would prefer to use the expensive, most accurate instruments. Those probably would be the sexy ones. Imagine instruments with precision you cannot fathom. For students again, one more important point would be the availability. For example, if a machine is more readily available they would buy it. Because they wouldn’t know of specific stores where high quality products might be available.
Can you narrow down what kind of test instrument you mean? I have a pair of vernier calipers in mind but personally I'd go for the most 'mechanical' looking over a curvier version, but this might change if it's a totally different kind of instrument.
Come on. There are rules of design, and pretty much any engineer should be conversant with them. Well, given that it is students we are talking of here, don’t you think they like trendy stuff, curvy as you say? Aesthetic appearance of engineering products serve as a number one marketing feature. Needless to say, the accuracy, reliability, precision, ergonomics and repeatability features have to be put into consideration. So if you really think of a product that appeals to a younger generation, make sure that it meets every engineering design need and then ace it up by making it appealing to the eye. You won’t regret it.
I'm not sure aesthetics is the number one feature for engineering tools, at all. I know whenever I buy tools I always look at the function first and ensure that it actually does the job well. I barely even register ergonomics (although I'm sure there's some subconscious element). If you look at your toolbox - how many things in there did you buy because they looked nice, and how many because they did the job well? Reading reviews of function is my biggest indicator of whether I'll buy something - I'm just sick of buying cheaply-made crap that breaks after a few uses, no matter how it looks.
Don't get me wrong. Aesthetics is not a number one, but it is important. From the response I made above, several crucial features have been mentioned.
