As promised, here's my comparison of both Warlord Games existing 28mm 1/56 resin and metal Tiger one, and also Rubicon Models new plastic Tiger. The Warlord model has the large patches of green and brown, whilst Rubicons is the lighter coloured vehicle. Rubicon's model wasn't finished at the time these pictures were take, so is still WIP.
As you can see from the photo's in terms of dimensions both are near perfectly compatible with one another. Rubicons model requires you to add Zimmerit, and being a plastic kit takes a little longer to assemble, however it does come with a large amount of optional parts to enable any Tiger variant to be built, and careful building would allow you to interchange the variants as well.
In conclusion, both kits are very nice, and largly come down to how much work you want to put into a model. Rubicons kit is stunning, and by sculpting Zimmerit on can result in a spectacular kit. (Or can be spectacular straight from the box if building an early version!) Warlords Tiger is also very nice with some great detail straight from the box, so ultimately pays your money and takes your choice. It's worth pointing out Warlord have announced a plastic late production Tiger as well, so it will be interesting to compare this to once it's released. As it stands Rubicons is also the cheaper of the two kits.
As always, more of my work can be seen at https://www.facebook.com/VolleyFirepainting