I'm not the most objective as I have not the expereince with other 
    loopers.  I do feel the RC-50 
gets a bad rap in reviews due to it's 
    complexity, and over-hyped by it's own liturature. 
I like the 
    way the midi out works for me. The place I got mine has another and I would 
    like to see
if the RC-50 would sync to it's own kind. I have heard the 
    problem is in using the midi in. I haven't 
had a need as my DR-5 syncs 
    to the RC-50 just fine. If I do use 2 units I would set them up in 
    single-mode and use the second unit to bring in multi-mode. 
It 
    can be set up with a feedback loop from the subs back to the aux input to 
    give decay while recording.  
It is also possible to have swell and 
    decay when loops are being stopped/started.  These 2 things are very 
    useful. 
As Buzap indicates, it does NOT handle tempo changes 
    well at all. While easy to set orginal tempo and send sync, it will not give 
    a good sound when tempo is changed.(warbled) 
There are a LOT of 
    menus for set up on the unit, some global and some patch/phrase specific, 
    which is nice.  The drawback I see might be the price depending what 
    you are looking for. I think you should try someones out that is familar 
    with it, before making a purchase. 
I like using a mixer with 
    the unit. 
Capt.