Opened him last night and had a play. My brief thoughts:
Robot Mode
Very good, very nice articulation, good weapons, good colour scheme, looks very much like he did in the G1 cartoon. A definite winner!
Vehicle mode
Just that bit too elongated with too much of a gap between the back of the cab and the front of the ladder rig. However I like the inclusion of a rescue bucket at the top of the ladder and it's fairly modern looking.
Overall
I've got GDO and Titanium Hot Spots and I was pretty happy with both. This beats them both however for the simple fact he combines with the other Protectobots to form Defensor. He is a decent sized toy without any major glaring faults, though I think his vehicle mode could have been a bit better. However if you were just after representation of Hot Spot, even though it is a recolour of RID Prime, the Titanium Hot Zone I think does the superior job of combining the look and feel of the original toy and cartoon incarnation.