Finally achieved the infamous Tiger I on my free WoT account! This was a LONG grind!
Both the tanks prior to this - the VK 36.01 (H) - and the un-upgraded Tiger I were absolutely abysmal tanks to play. The un-upgraded Tiger I - with the 'inferior' L/56 88mm gun - was just a big lump of target which asked to be arty fodder. In the end, just to grind to the upgraded L/71 88mm gun, I used the un-upgraded Tiger as a turreted tank destroyer and kept to long range sniping with Gold (silver) ammo!
Even upgraded the Tiger I has to be played very wisely and ideally still at long range as it has a tendency to catch fire very easily. Do not try an brawl with this tank (unless you definitely know you can win)!
As for upgrades, I have stuck in the gun-rammer - of course - and the binoculars to aid with long range sniping. General opinion seems to suggest that camo isn't worth it with this tank - it doesn't have that much effect, so I will go for ventilation to aid crew effectiveness. For crew training sixth sense is a MUST, and you can cut down on the fire issue by training for preventative measures. Driving skills help with mobility and any skill that aids view distance is an advantage.
Still, I proved my point, you can earn some of the bigger tanks using WoT freely (as opposed to Premium membership) if you are willing to put the work in grinding them...
As to what next, I think I will switch back to the Tank Destroyer line now and see how far I can grind up that tech tree.