Mine are the 2004 version using a normal rotor (not floating)Ever since I have had them (2004) I wouldn't say they are that powerful.
What should i expect power wise? I think I'd struggle to lock the wheel.

Would swapping to the floating rotors make them more powerful or rebleed and fit goodridge hoses? I have rebled successfully before but again they don't feel 'sharp'.

Should they feel 'on off' or more graduated?

Mine are the same, with 183mm floating rotors. Interested in how this thread turns out…

floating rotor not the way forward then? maybe goodridge hose and new normal rotors for me? See what folks think.

i had a similar age/performance set. could really have done with a complete overhaul, new pistons, seals, lever rebuild.

in the end i sold the set for £60 and bought some XT's for £100. way cheaper than the rebuild and significantly better brakes at the end of it…

Mine have the goodridge hoses as well…

I have a set of old M4's with the older lever (the M4's with different sized pistons) and a set of new ones (with the tech levers and identical sized pistons), both bikes have 183/160 floating rotors and if I grab the brakes I'll go over the bars or lock the wheel . . . one set run discobrakes sintered and the other still on the original hope pads . . . neither are on/off and that's the way I want them, plenty modulation . . . floating rotors are only an advantage where you are really cooking the brakes, they stop the disk getting warped . . . both sets have rock solid levers, I use a vacuum bleeder to bled them, perfect bleed every time . . .

When did you last change the fluid? Supposed to be every two years, that might help. I have Goodridge hoses and I've never had any problems, though I've never changed my fluid either!

I have the older ones with different sized pistons and they are bob on. They have hope braided hoses, "floating" rotors and set up properly they could stop a train. I am a lardy chap and they just work… 😀

…and squeal like hell at times. 😯

Apart from the floaters looking good and matching the colour of my hubs and piston caps I have not really noticed a gain in performance. 😳

I have a 2009 M4 on the front and an X2 rear, with floating rotors. They are ok but do require you pull the lever a lot harder than with some other brakes, modulation apparently! I have juicy fives on my other bike which are much more powerful.

I had the new tech lever hope m4s on my bike, and after 3 months swapped them for hope v2s BIG difference. I am a big guy (220 pounds) and just felt like the m4s were not that powerful.

V2s are great

I have some hope mono m4's, 180/160, and mono mini's on my other bike. I 've used avids, formulas and other hope models in the past. The mono M4's and mini's have similar power until you pull them harder and the M4's have more ultimate braking power, more than I really need. Compared to the avids and formula's there is a greater range of applicable power, modulation, before you reach the maximum braking power so they have much less on/off feel and need pulling all the way and reasonably hard if you want to stop fast.
Floating rotors won't make a difference, bigger rotors will make a big difference though. I have braided hoses on some of my brakes, they don't make a noticable difference but look good and flex much better for routing them around the frame. A good bleed, make sure there is plenty of pad and no surface contamination on the pads and rotors, use a good degreaser for brakes if there is. You could try sintered pads if you aren't already using them, and maybe larger rotors.

Glad not spent £60 on rotors then!
Does anyone think that they would benefit a rebuild?

There's no good reason for them to lack power

Before rebuilding
I would thoroughly degrease & clean the rotors & calipers, pads etc – hot soapy water & detergent will do it
It would be best to dismantle them
Then bleed the system
Give the braking surfaces of the pads a rotors a rub over with emery paper before reassembling

If you are getting muck passing the seals and contaminating the brake fluid or air passing the seals and getting air bubbles in the system so you need a lot of bleeding then a lever and caliper rebuild will replace the seals and make them much more reliable. If you don't find you have these problems then a complete change of fluid will probably be all you need. As already mentioned you should change the oil every two years as it breaks down.
A rebuild giving them new seals and fresh oil can't harm them and the fresh oil and good bleed should give you a better lever feel.

I would go for sanding the pads and diec and rebed in first.

It sounds to me like contaminated or glazed pads.

I had the same issues with some 2nd-hand Mono M4s (Black/Gold) and I even had Hope bleed/rebuild them.

They felt exactly the same, so I figured the problem lay in my setup.

Since discovering the videos (linked below) ALL my brakes are absolutely perfect -The "Centralising Pistons" one made a massive difference to the brake feel – I thoroughly recommend following the tips.

A ride in wet/muddy conditions beds new pads in perfectly.

Bleeding Brake Video

Rolling Diaphram Video

Set Up Caliper Video

Centralising Pistons Video