Guting and Shida are elementary schools in central Taipei near the university districts.
I know that Guting is considered to be a desirable elementary school by many Taiwanese parents. That probably means high academic standards and more pressure. Gutng is located at right by the TaiPower MRT stop but on the location of two very large multilane roads. I’d be concerned about the levels of pollution and noise. You could look for housing in Wenshan but I’m not sure you can enroll at Guting if you don’t live in its catchment area. It’s in Da’an and the area is expensive.
I don’t know anything about Shida. Do you mean National Taipei University of Education
Experimental Elementary School? That’s a school affiliated with a teacher’s college. They are usually considered to be very good. Again it’s in Da’an and an expensive area.
In 2016 your older child will be nine. He/she could have a tough time adjusting to a Taiwanese elementary school at that age. What about Taipei Municipal Nangang Elementary School (nkps.tp.edu.tw/)? Maybe your older child could go to the bilingual class and the younger to the ordinary program. Nangang is a less expensive area of Taipei.