Practical Pros and Cons of Steel vs. GRP

Possibly, but modern steel boats are generally pretty good. If it's a DIY then a survey will reveal the truth.
There are still some horrors around - even with so called professionally built boats. Particularly when the builders then attach teak decks to the steel structure and fill the inside with fittings you can't remove to see what is going on underneath. Having seen the bills for refurbishing a not very old so called high quality boat I would still be very wary.
 
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