The Tiagra 50 are an awesome reel but very expensive but a TLD50 is an awesome Fin reel that is also capable against most billfish. I owned a couple of these as well as 25's and 15's whilst working in PNG and have marked up many noteable catches including YFT to 85kgs and Billies to the mid 100's. They also only weigh a fraction of what the Tiagras do. Just keep them serviced and they will last for many years. While I had these I also had a full set (8,10,12,15,and 24kg) Fin Nor Ahabs and fished the TLD's more often than not, a very underrated and capable family of reels.
Cheers
Geoff