Which Saginaw P/S pump is the better one?

We now have two Saginaw pumps to choose from. One is referred to as the oval neck unit and as I understand it was used from 69-72 and the other is referred to as the box style unit and t was used from 69 - 74.

Does anyone know if both units perform equally?
If one unit is better than the other which one is it?

Here are the two Saginaw pumps for review:

https://scontent-a-lga.xx.fbcdn.net...268_685114954904215_8994374353920671623_o.jpg

https://fbcdn-sphotos-g-a.akamaihd....167_685114961570881_6566500120333490394_o.jpg

https://fbcdn-sphotos-b-a.akamaihd....786_685114951570882_1277812333853695645_o.jpg

https://fbcdn-sphotos-d-a.akamaihd....923_685115021570875_8662681346834805784_o.jpg

https://scontent-b-lga.xx.fbcdn.net...=69e7372ea7bd69a63942d65490d0b75e&oe=547592FA

https://fbcdn-sphotos-a-a.akamaihd....935_685115101570867_4654432543264127433_o.jpg