Is the TI 89 still useful or not?

[ehcheung]

I am a first year Petroleum Engineering student and I currently use a TI 83+. However, the TI 89 comes recommended from my math professor and TA. I have two questions:

1. Should I get one? It is that much more useful? How so? Pros and cons?

2. Should I get a TI 89 or a TI 89 Titanium? I've used 84's and I dislike their bulkiness and their buttons, so I lean towards the TI 89 which uses the same styling as the 83. What about performance differences? I hear that the regular 89 lacks some kind of root ability.

 

[Greg Bernhardt]

They can still be useful since they are specialized and some testing areas allow them but not smart phones. Here is a around comparing the two,
https://www.physicsforums.com/threads/graphing-calculators-vs-smartphones.944646/