Both Group and local markets are doing heavy personnel cuts recently, especially on technology functions. Outsourcing is becoming predominant, and key technical people with their bags of skills, knowledge and experience are leaving for better places.
Although generally speaking general technical personnel (e.g. data centre guys) is well paid, if someone is highly specialised or has lots of experience may get a much more profitable occupation from a consulting company or another telco. For instance if you are an experienced OSS/BSS or Network Architect, or a Security or Audit specialist, or a radio or backhaul wizard - in Vodafone you may fall short of 40% of your salary compared with other companies or simply specialised telecom firms, and you will be at risk of stagnating in the mud of Vodafone politics.
It is true that there is a renewed trend towards "focus on technical people", "technology academy", "retaining the best talents" and there was recently an attempt at mimicking (with little success) the "technology career paths" that many other companies had for decades; however, Vodafone is almost exclusively the battlefield of rampant, ignorant middle and people managers, is an extremely political environment, and the actual knowledge and understanding of the technical background and reasons for any topic is not necessarily useful - it only provides you a small edge for the sake of putting some salt in the discussion, but the decisions are always taken on other grounds but technical. I have personally witnessed "driven" RFIs/RFPs.
Company wise, Vodafone has been for a long time stuck in its strategy and lacked vision. It is a bit better with the actual CEO, although it may take lots of time to see the light at the end of the tunnel, and many of the changes that many had hoped for - speed, simplicity and trust - are still long to come. This is also because some of the premises are inherently faulty - you cannot for instance deliver a Cloud out of an rigidly ITIL and process built data centre where it takes 12 weeks and five Remedy ticket to just plug a cable. Other companies like Deutsche Telekom have correctly built brand new divisions for that and have done it much faster than Vodafone.
Take care that Vodafone is mostly enjoying its role as practically being the first or second incumbent telco in the countries it is present. Its main sources of income are Africa, India and getting dividends from Verizon Wireless; Vodafone is actually clueless and a (late) follower when it comes to any kind of innovation - it is solely an "adopter" and hardly any more bringing anything really innovative - R&D is a small, centralised and a few people worth function which is mostly there to trial technologies coming from outside. Its brand product are repackages of third parties, therefore if you are looking for any "startup-like" enthusiasm or you have brand new brilliant idea for the telecom market, despite the fact that they may tell you that they like it - they will because they need to increase their patent portfolio -, please forget Vodafone; you will just curb your enthusiasm over the time. For instance, you may think they could be doing anything innovative with LTE/4G or IPv6, while they are just waiting for Verizon Wireless to explain them how they did it, and then ask a third party to implement it.
Despite management saying the contrary, career paths' weight is being shifted towards UK more and more. If you are stuck in Germany you won't get past a certain physiological limits. And again, it is not a technological career. You need to pursue endless tiresome economy class travel just because your boss is a micro-manager and can't handle a virtual team. Or maybe, your team is made of a bunch of Indian people which are actually re-branded WiPro guys with a Vodafone badge, which will change every month, and that's all you'll get.
Finally, HR is worthless, especially in these times of personnel and cost reductions, lots of people are really getting mobbed and HR is hopeless. I know people who brought their reasons with a lawyer. Personal Dialogue is done "Microsoft way", they will pick up one bad and one good and keep the pack in the average - bonuses have a budget too, after all... Job changing is sometimes deliberately obstructed by your manager, and job rotation is also done without any kind of real budget and therefore not effective - it is mostly just an advertisement stunt for some HR manager, to "show off" "how good" we are. But they will not finance your move - no budget for that - so you can only swap job with someone working some desks next to you - not really a major change honestly.
Honestly you may like Vodafone or not - every answer can be two folded, depending on the kind of person you are. If you are the kind of person who enjoys building real, concrete products spurring from actual knowledge, this company is too volatile and you won't have opportunities - Vodafone only cannibalised knowledge, do not nurture it - it only buys it off the shelves from other companies. However, if you enjoy a "career" whatever that is and being promoted not because you accomplished but because *it looks like* you did - maybe you are a project manager?... -, then maybe Vodafone may offer some opportunities.
Personally I tried everything, but had to resolve leaving and I got a more fair treatment elsewhere.