Having persevered with 1x9 for a year I'm giving up the pain and going dual on my P7. being a standard hardtail frame I could fit either type of front mech but does one perform better than the other? Any advice on the best mech for £25.
If I have the choice, I think conventional(bottom swing) lasts better and is a bit easier to set up on the ones I've used. On my current hardtail I've had to go top swing as the clamp on a conventional would be in the way of a bottle cage. £25 should get an XTR secondhand or a £27 buys an XT M771 which will be well up to the job. Loads go for much less secondhand because of the 1x9 trend though.
As above, If I can I'll go bottom swing as although the distance between cage pivots is much shorter (ought to be less stiff), it doesn't build up mud like top swings do so should last longer too and keep away the slop/play used mechs can get.
You're much less likely to get the big mud build up around the chainstays too without a mech mechanism there too IME
Personally wouldn't go above SLX, if it wasn't for the main bike would probably just go deore or alivio (not got a proper reason not to go deore/alivio on the main bike but .. )
I find the top swing dual pulls easier to set up. I'd check the manufacturer's recommendations though....sometimes you have to go bottom swing because certain seat tube angles only allow certain mechs to work...
That's one of my own mistakes talking there!!!!!