Having used both I have to agree with Skoiboy, the new unit does feel far more precise and accurate in operation.
The design and build quality is far superior and is a major improvement over the MK 4, no more worries of accidental damage to the base or stem. Light filtering issues still exist (to be expected) but have been noticeably improved upon.
Is it worth buying if you are an existing owner of the MK4, then probably not? If you do not own a TIR and are planning to purchase then go for the MK5, there is a £20 difference in the U.K. (R.C Simulations)
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