I used a springer this past Saturday at a match (Phoenix Airgun Club at Rio Salado Sportsmans Club) and it was a blast.
You're right in your assessment however, the majority of shooters, at least here in the US, seem to be using PCPs.
I usually shoot a PCP as well. About the only time I use a springer is when I have arranged it with someone for them to also shoot a springer. Of the regulars, there are really only a handful of members in the primary club that I go to, that are willing to shoot a springer at a match.
As far being competitive......well, you're never gonna have as good of scores as the best PCP shooters if you're shooting a springer. However, you can compete with other springer shooters and still very much enjoy the sport. With realistic expectations, a "springer guy" can have a ton of fun at a field target match.
What would one use? It seems like the most common FT springers are the Air Arms TX200, HW97, Diana 54? (recoil-less sled springers) and Walther LGU. I shot a FWB 300s this past weekend. The 600fps with 7.87grain pellets (about 6fpe) was not enough to knock some of the targets down, even with clean paddle hits. I would not recommend going with that gun but it was sure fun. Anything past about 40 yards was a hope and a prayer. My offficial score was a 22/48. The new shooter I was shooting with (and had previously arranged the springer match) shot a very impressive 35/48 with a tricked out 11.5fpe LGU. His gun has an aluminum aftermarket stock, a Rowan knee riser, and a fancy aluminum butthook. Very nice rig. We were both shooting in the WFTF (no shooting harness or bipod and limited to less than 12fpe) class.
For comparison, my 22/48 was better than the couple lowest PCP scores but definitely on the lower end of the pack. My friend's 35/48 was better than quite a few of the PCP shooters (and even better than one of the PCP WFTF shooters) but was about mid-pack, when looking at the overall scores of all shooters.
Don't let not having a PCP keep you from making it to a match and having fun. There is lots to be said about the convenience of not being reliant on an air source. When just wanting a stress-free, enjoyable shooting experience, both at home and during a match, springers are where it's at. Springers are also quite the challenge, I consider it something like shooting traditional archery vs shooting a crossbow (PCP). Their is a certain nostalgia to shooting a springer. I quite enjoy it.