It makes no more than a couple of weeks difference to the minimum time to qualification!
The reasons I think it is such a poor option are numerous, but centre around cost and experience. You will come out of an modular course with an extra £12k+ and an extra 50 hours+. In addition you have held a PPL, and built hours while competent to sign a tech log yourself - you don't need any other authority to fly! You have true captaincy. The integrated course can limit your job opportunities because you lack the independent experience.
The reason I say there is a job for a 500-1000 hour pilot from a modular training is that some employers in light charter (I have only been in the business a short time, so I don't know how prevalent this is, but the reasons apply across the board) will not touch integrated graduates. They think that the course is far too geared to producing an airline FO, rather than a pilot first, so the FO can develop in MCC/type rating/line training. All the training is closely supervised, so they are not expected to fly independently until they are captains on an airliner! There are jobs around at the moment in light charter. I could have had any one of 3, and I didn't spread my net very widely. You need a minimum of either 400 or 700 hours for single-crew, but that is achievable if you look to the cheaper courses then use the money saved to instruct, or seeing as you are prepared to fly anything. People I know have used paradropping, glider towing, sales demonstrations and delivery flights all to increase their hours.
Oh, and I love this job!
If you want the airlines then there is no net benefit to the integrated course. There would be a small benefit, as there are a few airlines who express a preference (although evidence suggests this is not a very strong preference, even for those that nominally demand only integrated; I know of modular graduates who joined FlyBe when they did). However the money saved by going modular could be used for training that would step you above an integrated graduate to many other airlines which employ far more low-hour pilots.
You could become an instructor, keep your flying skills up and many companies like instructors. You could take a jet orientation course, not only improving your CV but some of which directly feed airlines, others just would give you a huge advantage in those sim rides that are not too hard to get but are hard to pass (others are harder to get, but not so hard to pass!). You could even get a turbo-prop type rating. A friend bought an ATR type rating, and was then not only approached by an ATR operator (he now flies for) but also by a Dash 8 operator. Another acquaintance was given 2 days to pack his bags, because he had an ATR rating and someone suddenly needed rated pilots for a contract they had won at short notice. You could put the money towards one of the riskier schemes, like Astraeus's rating/line training, or a jet type rating though I would recommend caution and a lot of research in this. I do know someone who got into Ryanair by the Astraeus route.
So integrated has very little benefit I can see. Certainly the reason you give is just propoganda from the integrated schools - my modular course at SFT was nominally 2 weeks longer than Cabair's integrated. The benefits certainly do not justify the costs.