This all depends on the grounds of the competition, whether it is launch vehicle development or operations costs, system safety, or just sheer performance.
Often solid boosters are quoted as being simpler to develop and fly, as they do not require plumbing systems and do not separate 'tanks' from engines. Liquid propellant stages will likely feature more complex engines - in many cases more than one chamber - and may also have to account for the issues of cryogenic storage. This is perhaps mitigated with pressure-fed liquid fuel designs (like Sea Dragon). Also, with breakthroughs from commercial companies, reusability may soon allow for liquid stages to simply be refilled and flown. SRBs must have their propellant cast again in a lengthy process involving some disassembly, if they are to fly again.
System safety is anyone's game in flight, though it appears more sway towards liquid fuels for their ability to shut off propulsion in an abort scenario. Solid fuel motors cannot throttle (but thrust profiles can be tailored before launch), and cannot shut down. However, we must remember that the increased complexity of many current liquid fuel launchers gives the possibility of many more potential failure modes.
But I commonly see the analysis of safety only extend to in-flight dangers. It is crucial to remember that a rocket spends a long time in preparation on the ground while awaiting launch, and here solid fuel motors lose. A motor casing must have its propellant cast well before launch, and this includes during vehicle assembly. As such, workers are placed in the presence of live stages (think Shuttle in the VAB). Liquid fuel staged need only be fuelled on the pad, just before launch.
Performance is liquid fuel's game for the most part, with its generally much higher specific impulse. However, the battle for Isp is not most important during the first portion of ascent. From reading papers on proposed Shuttle liquid booster programs, it is 'impulse density' that wins here. Rather than simply exhaust velocity, an engine must combine that with reaction mass to achieve optimum figures (or something like that - where is that paper anyway!?) As you may see, this appears to say high thrust and fuel storage are what you're looking for, and SRBs have it all there - dense propellant and massive burn rates. This holds true for many liquid rocket stages as well - the Saturn V first stage's heavy launch mass and low specific impulse were less of an issue, because combined with its massive thrust it could generate delta-V against resistance from gravity and drag losses. It is these losses that ultimately define the design of lower stages.
About the rockets you listed - the Shuttle, Ariane 5 and Titan IV. Do you notice any similarity between their designs?
All three feature two SRBs around a high-performance, and long burning, liquid fuel core stage. The solid boosters provide most of the thrust at liftoff and then separate after a short burn, while the core does most of the work in reaching orbital velocity. This makes the core into what is known as a 'sustainer.' Basically, it is what makes a two-stage rocket out of a 'stage-and-a-half' boosted design (Titan's first stage is perhaps less suited to this, but it's core is not a LH2 stage and is less efficient than the others - thus it has more upper stages). The first stage, according to this, is the two solid boosters AND the core, together. The second stage is that very same core, without boosters. The core features an engine with high Isp but lower thrust and fuel mass, great for an upper stage but not for a first. The boosters feature a low Isp but massive thrust and fuel capacity - so, when combined, the boosters lift the core and fuel through atmospheric resistance, while the core slightly increases the overall Isp of the first part of the ascent. It's like having a normal first stage that is slightly more efficient than the boosters themselves.
Long answer short: solids shouldn't have to compete - they're best when they work with liquids, not by themselves.
Just no messing around when the thing is on the ground...
(By the way, that 'impulse density' stuff has escaped me for the moment. I hope it's correct, but if not, please forgive my forgetfulness!)