First, let me say that this is really the wrong forum in which to ask this since none of these phase shifters are EHX products although at least one is a direct EHX clone. I’ll answer your question, but my recommendation will follow. Phase shifters are PRIMARILY categorized by the number of “stages”. Very generally every two stages will give you one filter “notch”. So, a two stage phase shifter will give you one notch.

MXR Phase 90 – Probably the most copied phase shifter. 4 stages give you 2 notches. The EHX Small Stone is also a 4 stage phase shifter, but sounds different.

Behringer Vintage Phaser – This is a clone of the original EHX Small Stone. It sounds pretty close, but the taper of the knobs is different.

Earthquaker Devices Grand Orbiter Phase Machine – 4 stages like the Phase 90 and the Small Stone. Lots of control over parameters – depth, feedback, etc. Maybe too much control?

MXR EVH90 Phase 90 – Branding. This is a Phase 90. Again, 4 stages. Slight tweaks of the filters, but it’s basically a Phase 90.

Joyo JF-06 Vintage Phase – Yet another Phase 90 clone. I’m sure it’s close, but it’s probably digital rather than analog.

KOKKO FPH2 Phaser – I don’t know anything about this one.

Moog MF101 Moogerfooger Low Pass Filter – Of course the Moog is awesome and fantastic. Be prepared to pay the big bucks for this baby. It’s not going to sound like a Phase 90 or a Small Stone. It’s going to sound like a very powerful, flexible, clean, SYNTHESIZER phase shifter. Not pedalboard friendly. Not wallet friendly. Not the “classic” rock guitar phase shifting sound.

MXR M290 Phase 95 – This is an interesting pedal because it lets you switch between the Phase 45 which is a 2 stage phase shifter and the Phase 90 which is a 4 stage phase shifter. It also has a “Script” button which lowers the feedback for a more “subtle” sound which is actually more like the EHX Small Stone with the COLOR switch up. I don’t have experience with this pedal, but if you’re definitely looking for the Phase 90 sound, this might be the way to go. It doesn’t look like it can be battery powered, and it MIGHT be a digital circuit which is a bit of a turn off for me.

TC Electronic Helix – TC Electronic makes good pedals. Lots of options. Lots of sounds. I’m pretty sure it all digital. Stereo – that’s nice. It’s just TOO MUCH STUFF for most people. Most people dial in a setting they like and they leave it there. Over the years LOTS of people have come to the conclusion that they really like either the MXR Phase 90 or the EHX Small Stone. They sound slightly different. So why pay more money for extra knobs and settings that you’ll never use? If you’re looking for a very tweakable pedal for studio use this might be the one for you.

Walrus Audio Vanguard Dual Phase – Walrus makes great stuff. This is the most tweakable phaser on this list. It’s the only one that gives you an option for 6 stages (3 notches) of phase shifting. It’s an awesome pedal that costs a lot of money, takes up a lot of room on your pedalboard, and gives you so many features that you probably won’t use 90% of them.

Earthquaker Devices Grand Orbiter – Earthquaker makes awesome pedals. This is no exception. It’s a very tweakable 4 stage (2 notch) phase shifter. Lots of tweaking. Expensive.

Now, these are EHX’ offerings:

Small Stone – Probably the second most replicated phase shifting circuit after the Phase 90. LOTS and LOTS of people use the Small Stone. The Nano version is very pedalboard friendly, it’s quiet, it can run on batteries, it’s extremely affordable, the new psychedelic 60s one looks great. You set the one switch and the one knob to a setting that you like, and you’re good to go. It’s a 4 stage (2 notch) phase shifter like the Phase 90, but it’s a different circuit. It’s NOT a Phase 90 clone.

Bad Stone – A 6 stage (3 notch) version of the Small Stone circuit. The MXR Phase 100 is also a 6 stage phase shifter, but they are NOT clones of each other. 6 stage phase shifter have a “sharper” or more “intense” sound.

Worm – The Worm contains a 3 stage (!) phase shifter that is intended to sound more like a Univibe type of phase shifter.

Good Vibes – This is an EXTREMELY FAITHFUL Univibe clone. It uses lamps and photoresistors to control the LFO. The Univibe is actually a phase shifter, but it’s such a unique circuit that it’s generally considered separately. The classic Univibe song is Bridge of Sighs by Robin Trower. The EHX Good Vibes nails this sound and sounds awesome.

There are some other EHX pedals that have phase shifters in them, but they try to sound like one of these.

Bottom Line?

Forget this list. Get yourself a Small Stone and you’ll be very happy.