My arcade stick experience is minimal but I wanted one for SFIV as joypads weren't cutting it, so this review is coming from an arcade stick novice.
I had seen an HORI EX2 arcade stick for about £45 so I did some research on arcade sticks and opened up a can'o'worms! I wanted a quality stick that would last but not something too expensive so after reading multiple reviews/forums about what seem to be the 2 main rivals (HORI and Madcatz) it seems as though one conclusion was clear:as long as what you buy has buttons and a stick made by SANWA(makers of authentic arcades in Japan)or Seimitsu, you are guaranteed quality.
The Madcatz STIV Tournament Edition Round 2 is highly regarded (though seemingly extremely expensive if it's not second hand as they seem to be difficult to find nowadays, but that's just my experience) and the Real Arcade Pro VX SA is HORI's answer to this (for Xbox and V3 SA for PS3). Both have SANWA joy sticks and buttons (lesser arcade sticks only have SANWA joy sticks but not buttons or no SANWA parts at all)so with this in mind (and the price difference), HORI RAP VX SA was an easy choice.
It's my first stick so I can't compare it to the Madcatz STIV TE R2, but I can safely say that for fighting games that use a 2D model (SFIV, MK, KOF, BlazBlue), there is no going back to joypads. It doesn't make you a better player as timing is key for combos and in depth knowledge of the game will make you better,but the fluidity and ease which you can do the moves was clear;I had problems with 'L shaped' special moves (Guile and Vega)but the stick made it so much easier. It is a square gate stick but this quickly felt comfortable (those used to an octagonal/circle gate may find this a problem). The buttons are responsive and the arcade cabinet doesn't move around when you use it. 2 rows of 4 buttons (as opposed to 2 rows of 3) is practical but takes a little getting used to. The position of the start button could be better but wasn't a huge problem. Overall, the button spacing felt natural.
Unfortunately (and ironically)the HARP VX SA arrived with a malfunctioning 'A' button, so I have to hand it back immediately. However, for the brief time that I practiced with it, the difference from joypads was clear. Wonky button aside, it is a great and essential 2D fighting/arcade game accessory. Highly recommended.