Making a small list.
M577 CPC and G have very good armour and no weapons for 220 points, and a bucket of health.
Sultan has side armour, high speed and a MMG for 230 points.
M114A1 has a MMG and armour all around for 240 points, and a bucket of health.
VAB has a HMG and high speed with a bit of frontal armour for 240 points.
Brom 2D has high speed, low armour, no weapon, for 220 points.
BRM1K has good armour, a weak canon, and exceptional sights for 260 points.
Well, I guess you are somehow right. Comparing M577 and M114, you take 20 more points for an MMG and less armour.
However, I found that against air units madly rampaging over woods, if my VAB PC is in the middle of a group of (separated) VAB transports, my opponent takes a lot more time finding which one is the good one. The HMG (good against helos to be honest) is part of the camouflage for that one.
The Sultan however is rightly priced for its speed. Slightly the same with the VAB that is able to go far and fast.
The Brom 2D is unarmed and traded armour for speed: Fine. Good price.
BRM1K os an odd one, but has its own advantages justifying its price.
BRM1K has good armor? lulz. It is 1/1/0/0/ compared to the 220 M577G 2/1/1/1 armor
Also, I happened to make this same thread yesterday! viewtopic.php?f=12&t=3539