They have an Opel Blitz/Maultier on pre-order. It includes a sprue of seated troops. They haven't been doing these kinds of figures very well - they tend to be lumpy and less detailed than their multipart infantry. This is the only subject that overlaps Rubicon. I'm going to bet Rubicon's Maultier is better.
Hard to say Pinky. As you can see, I have them all (both Rubicon kits and the Warlord kit).
How different are they?
Well, pretty different.
That being said, both the Rubicon kits and the Warlord kit are good kits. I can't say which is better because that would like comparing German chocolate to Belgium chocolate. To me, both are very good and worth getting.
Because I have the different ones in my hands, you might ask, "If I had to choose between the two, which one would you pick?" That is no easy answer, but instead I will look at certain aspects.
Driver and passengers:
Both kits come with drivers, but the Warlord kit comes with passengers. Is this critical? No, not at all. And if it was, the Warlord passengers can be purchased separately and added to a Rubicon build.
Plastic:
The plastics used to make the models are different. The plastic used by Rubicon seems to be better.
Decals:
Both kits come with really a nice decal sheet with lots of options, but as for decal material, I tend to like the Rubicon decals better because they have a really thin film. While this may give troubles to new model builders as well as some experienced model builders, they are easy to work with once you start learning how thin the decals are. Also, at first, I was worried that the Micro-Sol (from Microscale) would be too strong to use, and thought I would only use the Micro-set. However, Micro-sol works as it should.
Choices:
Here I think the Warlord kit pulls ahead. The Warlord kit gives you the choice to build an Opel Blitz or a Maultier while the Rubicon SdKfz 305 kit only allows you to build the Opel Blitz. However, the Rubicon SdKfz 3a Maultier kit does give you the bits to build either an Opel Blitz or Maultier even though the instructions do not tell you this and suggest you can only build the Maultier. I think Warlord has done the correct thing in that it made their kit so that either can be built.
As a Model:
Both kits build up very nicely and have pretty good details. It needs to be said that both the Rubicon kits and the Warlord kit are very easy builds. For a model building (not gamer) making dioramas, I have to say the Warlord kit does give you the possibility to assemble the kit with doors open or closed (doors are separate pieces). I built my Warlord kit with doors closed, so unless someone wants to build a vignette as a show piece or objective marker for their games showing the model with open doors, having open or closed doors as an option is not that big of a deal. Besides, Rubicon's one piece cab is probably nice for some wargamers that are not enthusiastic about building model kits.
Overall:
No matter which kit you choose, you will have a nice model for gaming or display. For me, the most deciding factor is availability because it is easier for me to purchase the Warlord kit than the Rubicon kits. On top of that, the Rubicon kits come with a shipping cost (mail order) as well. When taking cost into account, the Warlord kit is a little less expensive (for me). If I had to get lots of Opel Blitz or Maultiers, I think I would end up getting more Warlord kits than Rubicon kits.