ive played a few. i wasnt a big fan of the intellijel uvcf i had, but all the others have sounded good.
i wasnt fond of the control scheme of the lxd or the z2040, but they were both easy on the ears.
the doepfer lpg has a mean preamp and sick resonance and a little pricetag.
filters are fun modules to play manually so id look for one with a nice layout and cool features.
i remember really wanting voltage control of resonance, and feeling like i miss it when i play a filter without kt, but i cant remember ever using it a whole lot ;_;
a modulars a very personal thing so do some window shopping on youtube , figure out if you want low pass or state variable, 12 dB or 24 dB, &c
-- moremagic

Thanks for this input!

If you have guitar effects pedals/stompboxes, there are modules that allow you to use those in your modular setup as well. I don't play guitar but since one of my builds is a Rackbrute 3U (small footprint), I got the Bastl Hendrikson which will allow me to use external stompbox (plural when I get a Electro-Harmonix Tri Parallel Mixer, which will let me connect up to 3 external pedals).
Hendrikson is discontinued but ALM also makes one called ALM006 - S.B.G...just something to consider since you play guitar and may have some effect pedals...or this would give you another reason to buy one :)
-- jb61264

Thanks -- yes, a later purchase is likely to be a floor control or one of the ones you mentioned. I don't want to start too complicate -- so initially just want to focus on the modular stuff by itself.

there are a load of these modules - not just the bastl and alm - doepfer, ime, etc etc
some pedals don't need them - moogerfoogers are generally ok with modular levels and my strymon mobius works fine with them - if you need a bit of a boost to get back in to the modular, some vcas (veils, for example) work perfectly well
one thing to note with guitar pedals is they often don't work that well with bass frequencies
-- JimHowell1970

Thanks! I am planning an Ears for boosting guitar signals into the modular system.