If the VX-150 didn't come with an extra battery it would be easier for me to decide, but that is a pretty good $40-$50 value.
The stock 150 battery is a 700mah nicad battery. 170 comes standard with the 1400mah NimH battery. Even with two batteries, I vote for the 170 on that issue if you're going to be using the stock batteries.
The 170 has the larger screen, but the 150 has the angled screen which seems to be more ideal when wearing on the belt, or carrying in the cup holder of the car.
The screen on the 170 looks great to me, if you can get by with the smaller 150 screen I do agree the angle would be helpful. I had a top display motorola MT2000 and that was handy. For my eyes though, I say the 170 wins again. The VX150 can show all seven digits for a frequency (in case you have a splinter and/or narrowband programmed) or a segment alpha-numeric display.
http://www.universal-radio.com/CATALOG/ht/3187lrg.jpg
The VX170 can only have a six segment alpha-numeric display, but it would be large :lol:
While the 150 is rugged, I would bet the 170 is as rugged, if not more. You can also get a VX177 later if you'd like a monoband 440 HT to be a matching radio, without having to re-learn anything.
If it were me and I bought either radio, I would likely get two AA cases, fill them with 2000mah eneloop AAs and sell the battery/batteries to someone else anyway :lol: Both of the radios share the same AA case, so I guess we could safely say that they can use each others batteries as well. Since the 150 is so much older, they are wanting to get rid of what they have and the smaller capacity batteries with it.
....edited to add more info and to move things around....