It's a good question, but I think the answer is starting to become clear.
Txiki Begiristain joined Manchester City in October of 2012 and from that day forward he has appeared to operate in a quiet and calm manner. Media interviews have been scarce, targets have been identified and acquired in a swift manner (save for Mangala), and the fans, notoriously difficult to please, seem to be, well, pleased with the players recruited during Begiristain's reign.
Beiristain will likely be seen as a success or a failure according to how well he operates in the high profile or area of player recruitment.
Some of those Begiristain recruits:
Fernandinho, Demichelis, Navas, Negredo, Jovetic, Caballero, Sagna, Fernando, Zuculini and Mangala.
Zuculini is a prospect, Mangala and Jovetic were bought for the future and for their considerable contributions to the now, the rest are buy now, perform now purchases.
But it's not just the acquisition of first team players that Begristain has overseen, it is the continued restocking of an often maligned youth setup.
Jason Denayer, Pablo Maffeo, Angelino, Thierry Ambrose, Zack Faour, Manu Garcia, Rodney Kongolo, Nwakali and most importantly, the very special Kelechi Iheanacho
Maybe these young guys make it, maybe they don't. But work is being done at both senior and youth team level. But we've not yet arrived at the best of Begiristain's work....
Exact transfer fees are usually pretty unpredictable.
Mario Balotelli £19m rising to £22m
Became a problem for Mancini and the club in general. High fee was extracted due to age and potential. Fine work.
Jeremy Helan £300k
Prospect who never pushed on. A buyer was found. Standard deal.
Scott Sinclair £1.3m loan fee
Not really a City player, Begiristain wasn't slow to fix the previous regimes mistake. A fee for a Scott Sinclair loan.
Carlos Tevez £10-12m
A genuine talent, but was likely not worth the trouble. Good fee for a 29 yo.
Gareth Barry Loan, wages paid, £2.5m buy fee
Barry was surplus to requirements after the Fernandinho signing, although some City fans continued to insist that it was a mistake to loan Barry and his huge wages. It soon became clear that it wasn't a mistake when Fernandinho began moving through the gears and FFP considerations were accounted for. A fine deal.
Jack Rodwell £10m
Played just 950 minutes during his 2 year stay. Likely not good enough for where Man City are at, and clearly not healthy enough either. That a fee, and not a loan, was secured is amazing work. That the fee is £10m is incredible.
Javi Garcia £12m
This transfer should go through pretty shortly. Garcia is actually a useful player who had some important moments for Manchester City but he is likely a little too one dimensional to be a key squad member. A high fee for what he is.
If we add the potential sales of Sinclair, Richards, Guidetti and possibly Nastasic to this list and it starts to look like a really impressive body of work.
Begiristain has shipped out players from Man City without hurting the squad depth or the starting XI. A total of around £57m has been banked for players who were either trouble, too old or simply not good enough. Begiristain has not only found buyers for these very well paid players but has likely extracted above sensible market value for each major sale. £57m may seem like small fry, and it is compared to the money spent on new players, but securing fees and shifting £'s off of the wage bill is important work.
Personally, I think Begiristain easily won the deal for the players shipped out on loan, extracted plus value for the Balotelli, Garcia and Rodwell sales and it feels like the only deal that Man City may have lost was the Tevez deal. But if we consider Tevez's age, his potential decline, clearing his wages and not to mention the trouble he caused then, logically, even that sale could be classed as a win.
Txiki Begiristain's job is a complex, multi-faceted one. Acquiring players is an incredibly important part of his job, but almost as important is finding buyers who will not only take Man City's unwanted players, but who will also overpay for them.
Begiristain has done fine work here. And I think he will continue to do fine work in the very near future.