Cheers mate, its a passion of mine that's for sure. Cannot wait for better weather though.
dude some kick ass work. you, unlike many photographers go and shoot. many are all about the gear but dont ever go out to shoot.
OP, since you said these 2, then its the tamron. I would ask you to take a look at the 105 AFD thats about $350 mint used and dont leave out the tokina 100 which is one sharp MF lens.
I personally dont think ken rockwell can review photography as his work sucks ass, but technical stuff he knows his stuff. and I hate that he begs for money from people and drives a mercedes and does pretty well. but you should at least read the review for the tokina
Tokina 100mm f/2.8 Macro Review
before I bought my 105VR I invested a huge amount of energy to see what was out there and read tons of reviews on them. imo, the tokina is superior to them all, including the 105VR, I shot it and at 2.8 its just sharp and focus is fast and bokeh is wonderful, but not as good as the 105VR and I needed the VR so got a used mint VR with warranty for a nice price. dont ignore the tokina. its built like a tank, has fast AF, will give you better working space, very sharp and amazing bokeh. if you have or plan to get an 85mm some time then the tamron at 90 is not the smarter choice. but you decide what you will. your money. good luck whatever you choose.