It's a mixed bag, nun.
I hired in about 28 years ago. There were two schemes on offer, one with higher monthly deductions, and one with less. They were the standard British pension schemes (defined benefit) where there is a pension department with the funds going into a pension trust. The trust is standalone. The trust hires a group of investment consultants to invest the funds. When you retired, you were paid by funds from the trust.
About 8 years ago the scheme was split (I'm fuzzy on this since I had already retired and didn't really care about what was happening for those still employed). New hires were offered the chance to join the existing scheme, or they could opt for various other types of pensions. The new hires who opted into the existing scheme went from a defined benefit pension to a defined contribution pension. I seem to remember there were also stakeholder/SIPP type offerings which were under limited company control.
Today, you have the remnants of the old scheme (defined benefit, and now defined contribution) combined with those new to the company on the new type schemes.
The restrictions in my previous post apply to the old scheme (those under the trust). New employees now have the options similar to what you are discussing is the norm in the States. I always stay out of conversations on this site when newly arrived US people talk of pensions from an UK employer. These days, it could be one of many 'types' of pensions, and each scheme seems to have small variations as to how the scheme is controlled.
For the scheme I'm familiar with, it's a transition period. Those who hired in 30 - 40 years ago are being held to the scheme rules in the previous post (financial expediency, I presume, to keep the trust fully funded). But, you have some new hires who now control their own pensions and in reality (I assume) the company doesn't really want to know about it. If I remember correctly, it was around 1975-80 when US company schemes started to change to the (new then) IRA type schemes and away from the old defined benefit schemes. Today, are there any defined benefit schemes left in the US? They are rapidly fading in the UK.
The new legislation (take the money and run upon retirement) appears to only actively apply to schemes where, instead of going into a standalone perpetual trust, the funds were required to be changed to an annuity (variable according to the economy at the time)upon retirement, so completely different to the traditional defined benefit pensions. With the current economy appearing destined to remain tight, the requirement to have an annuity became a penalty , and the Chancellor proposed the new 'take the money and run' option to appease those unhappy with the situation.
For someone such as yourself who is knowledgeable and proactive on investing, the US system works well. For those less inclined to be involved in investing, the old system worked well. The problem today is for those who are reticent to become involved, but are in the new US type schemes. Then Osborne throws in the wobbly 'go buy a new Roller' instead option.
Sorry for the rambling. DR:TL