Decent feather shuttles will be slower than nylon. This really comes down to a decision for your group. It sounds like it's a social group (not a tournament playing group), so if you all agree to continue playing with nylon, that should be fine. The point is to have fun.

I fully agree with the points already made. It is what is cost effective and fun for you and your friends that matters most. The transition from nylon to feather can be tricky, I remember it taking me a couple of sessions to sort my timing out when I started to regularly play with feathers.

The only point I would raise is regarding your development as players. If you just want to play as a group then that's fine, but if you want to push on and play within a club or try some league matches, you will HAVE to play with feathers. Just something to bear in mind.

I notice you are showing as being in Crosby, I play at a club in Maghull that is open to all abilities and age groups. Feel free to PM me if you would like more details.

cant imagine why they'd think feathers were slower,  unless the plastic were the really fast type  ( Red for Yonex,  Paul ?)  and then when they used “normal” speed feathers they are finding they need to hit harder. 

There may be a few other things that may cause them to think feathers are slower than plastic,  but they all come down to technique,  and without making assumptions about your friends and thier level of play I wouldn't want to comment.

I found feathers hard to control after playing at a social club who only use plastics (during a break from competitive badminton.)  But once you get a feel for feathers,  and how little effort is required to generate power, and the beauty of the sound you get from really connecting with a feather,  not sure it'd be possible to go back to nylon.

I am intrigued at this shuttle speeds issue as well.

For example.. what shuttle speed do olympians use ?

Take Carlton shuttles for instance…..Their GT1 range.. which states ;

First grade feathers of the highest specification, as used in international events. Approved by the Badminton World Federation for international play. Speeds available 76, 77, 78, 79.

This implies that any of those speeds could be used in an olympic game but I cannot believe that before each game the contendors test the speeds time after time….  and what if the contendors do not agree with the speed selected ? Do they have to agree on a speed between the two ? What if one player wants speed 78 and the other speed 79 for instance? Do the players test the shuttles before the game ?

In football.. the match ball is defined to specific size and usually for an event (e.g a world cup), a specific ball is made.. does this also occur in badminton and if so, is a specific speed used ?